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>What is the main purpose of a DNS server?
DNS servers are used to resolve FQDN hostnames into IP addresses and vice versa.
>What is the port no of dns ?
53.
>What is a Forward Lookup?
Resolving Host Names to IP Addresses.
>What is Reverse Lookup?
It?s a file contains host names to IP mapping information.
>What is a Resource Record?
It is a record provides the information about the resources available in the N/W
infrastructure.
>What are the diff. DNS Roles?
Standard Primary, Standard Secondary, & AD Integrated.
>What is a Zone?
Zone is a sub tree of DNS database.
>Secure services in your network require reverse name resolution to make it more
difficult to launch successful attacks against the services. To set this up, you
configure a reverse lookup zone and proceed to add records. Which record types
do you need to create?
PTR Records
>SOA records must be included in every zone. What are they used for ?
SOA records contain a TTL value, used by default in all resource records in the zone. SOA
records contain the e-mail address of the person who is responsible for maintaining the
zone. SOA records contain the current serial number of the zone, which is used in zone
transfers.
>By default, if the name is not found in the cache or local hosts file, what is the
first step the client takes to resolve the FQDN name into an IP address ?
Performs a recursive search through the primary DNS server based on the network interface
configuration .
> What is primary, Secondary, stub & AD Integrated Zone?
Primary Zone: - zone which is saved as normal text file with filename (.dns) in DBS folder.
Maintains a read, write copy of zone database.
Secondary Zone: - maintains a read only copy of zone database on another DNS server.
Provides fault tolerance and load balancing by acting as backup server to primary server.
Stub zone: - contains a copy of name server and SOA records used for reducing the DNS
search orders. Provides fault tolerance and load balancing.
> How do you manually create SRV records in DNS?
This is on windows server go to run ---> dnsmgmt.msc rightclick on the zone you want to
add srv record to and choose "other new record" and choose service location(srv).
> What is the main purpose of SRV records ?
SRV records are used in locating hosts that provide certain network services.
> Before installing your first domain controller in the network, you installed a DNS
server and created a zone, naming it as you would name your AD domain.
However, after the installation of the domain controller, you are unable to locate
infrastructure SRV records anywhere in the zone. What is the most likely cause of
this failure ?
The zone you created was not configured to allow dynamic updates. The local interface on
the DNS server was not configured to allow dynamic updates.
> Which of the following conditions must be satisfied to configure dynamic DNS
updates for legacy clients ?
The zone to be used for dynamic updates must be configured to allow dynamic updates. The
DHCP server must support, and be configured to allow, dynamic updates for legacy clients.
> At some point during the name resolution process, the requesting party received
authoritative reply. Which further actions are likely to be taken after this reply ?
After receiving the authoritative reply, the resolution process is effectively over.
> Name 3 benefits of using AD-integrated zones.
Active Directory integrated DNS enables Active Directory storage and replication of DNS
zone databases. Windows 2000 DNS server, the DNS server that is included with Windows
2000 Server, accommodates storing zone data in Active Directory.
When you configure a computer as a DNS server, zones are usually stored as text files on
name servers that is, all of the zones required by DNS are stored in a text file on the server
computer.
These text files must be synchronized among DNS name servers by using a system that
requires a separate replication topology and schedule called a zone transfer However, if you
use Active Directory integrated DNS when you configure a domain controller as a DNS name
server, zone data is stored as an Active Directory object and is replicated as part of domain
replication.
> Your company uses ten domain controllers, three of which are also used as DNS
servers. You have one companywide AD-integrated zone, which contains several
thousand resource records. This zone also allows dynamic updates, and it is
critical to keep this zone up-to-date. Replication between domain controllers takes
up a significant amount of bandwidth. You are looking to cut bandwidth usage for
the purpose of replication. What should you do?
Describe the importance of DNS to AD ?
When Microsoft began development on Active Directory, full compatibility
with the domain name system (DNS) was a critical priority. Active Directory
was built from the ground up not just to be fully compatible with DNS but to
be so integrated with it that one cannot exist without the other. Microsoft's
direction in this case did not just happen by chance, but because of the
central role that DNS plays in Internet name resolution and Microsoft's
desire to make its product lines embrace the Internet.
While fully conforming to the standards established for DNS, Active Directory
can expand upon the standard feature set of DNS and offer some new
capabilities such as AD-Integrated DNS, which greatly eases the
administration required for DNS environments. In addition, Active Directory
can easily adapt to exist in a foreign DNS environment, such as Unix BIND,
as long as the BIND version is 8.2.x or higher. When Microsoft began
development on Active Directory, full compatibility with the domain name
system (DNS) was a critical priority.
Active Directory was built from the ground up not just to be fully compatible
with DNS but to be so integrated with it that one cannot exist without the
other. Microsoft's direction in this case did not just happen by chance, but
Change the replication scope to all DNS servers in the domain.
>You are administering a network connected to the Internet. Your users complain
that everything is slow. Preliminary research of the problem indicates that it takes
a considerable amount of time to resolve names of resources on the Internet.
What is the most likely reason for this?
DNS servers are not caching replies.. Local client computers are not caching replies… The
cache.dns file may have been corrupted on the server.
because of the central role that DNS plays in Internet name resolution and
Microsoft's desire to make its product lines embrace the Internet.
> What is the "in-addr.arpa" zone used for?
In a Domain Name System (DNS) environment, it is common for a user or
an application to request a Reverse Lookup of a host name, given the IP
address. This article explains this process. The following is quoted from RFC
1035: "The Internet uses a special domain to support gateway location and
Internet address to host mapping. Other classes may employ a similar
strategy in other domains. The intent of this domain is to provide a
guaranteed method to perform host address to host name mapping, and to
facilitate queries to locate all gateways on a particular network on the
Internet.
"The domain begins at IN-ADDR.ARPA and has a substructure which follows
the Internet addressing structure. "Domain names in the IN-ADDR.ARPA
domain are defined to have up to four labels in addition to the IN-
ADDR.ARPA suffix. Each label represents one octet of an Internet address,
and is expressed as a character string for a decimal value in the range 0-255
(with leading zeros omitted except in the case of a zero octet which is
represented by a single zero).
"Host addresses are represented by domain names that have all four labels
specified." Reverse Lookup files use the structure specified in RFC 1035.
For example, if you have a network which is 150.10.0.0, then the Reverse
Lookup file for this network would be 10.150.IN-ADDR.ARPA. Any hosts with
IP addresses in the 150.10.0.0 network will have a PTR (or 'Pointer') entry in
10.150.IN- ADDR.ARPA referencing the host name for that IP address. A
single IN- ADDR.ARPA file may contain entries for hosts in many domains.
Consider the following scenario. There is a Reverse Lookup file 10.150.IN-
ADDR.ARPA with the following contents: Exp : 1.20 IN PTR WS1.ACME.COM.
> What are the requirements from DNS to support AD?
When you install Active Directory on a member server, the member server is
promoted to a domain controller. Active Directory uses DNS as the location
mechanism for domain controllers, enabling computers on the network to
obtain IP addresses of domain controllers. During the installation of Active
Directory, the service (SRV) and address (A) resource records are
dynamically registered in DNS, which are necessary for the successful
functionality of the domain controller locator (Locator) mechanism.
To find domain controllers in a domain or forest, a client queries DNS for the
SRV and A DNS resource records of the domain controller, which provide the
client with the names and IP addresses of the domain controllers. In this
context, the SRV and A resource records are referred to as Locator DNS
resource records.
When adding a domain controller to a forest, you are updating a DNS zone
hosted on a DNS server with the Locator DNS resource records and
identifying the domain controller. For this reason, the DNS zone must allow
dynamic updates (RFC 2136) and the DNS server hosting that zone must
support the SRV resource records (RFC 2782) to advertise the Active
Directory directory service. For more information about RFCs, see DNS RFCs.
If the DNS server hosting the authoritative DNS zone is not a server running
Windows 2000 or Windows Server 2003, contact your DNS administrator to
determine if the DNS server supports the required standards. If the server
does not support the required standards, or the authoritative DNS zone
cannot be configured to allow dynamic updates, then modification is required
to your existing DNS infrastructure.
For more information, see Checklist: Verifying DNS before installing Active
Directory and Using the Active Directory Installation Wizard.
Important
The DNS server used to support Active Directory must support SRV resource
records for the Locator mechanism to function. For more information, see
Managing resource records. It is recommended that the DNS infrastructure
allows dynamic updates of Locator DNS resource records (SRV and A) before
installing Active Directory, but your DNS administrator may add these
resource records manually after installation. After installing Active Directory,
these records can be found on the domain controller in the following
location: systemroot\System32\Config\Netlogon.dns .
> What does a zone consist of & why do we require a zone?
Zone consists of resource records and we require zone for representing sites.
> What is Caching Only Server?
When we install 2000 & 2003 server it is configured as caching only server
where it maintains the frequently accessed sites information and again when
we access the same site for next time it is obtain from cached information
instead of going to the actual site.
> What is forwarder?
When one DNS server can?t receive the query it can be forwarded to
another DNS once configured as forwarder.
> What is secondary DNS Server?
It is backup for primary DNS where it maintains a read only copy of DNS
database.
> How to enable Dynamic updates in DNS?
Start>Program>Admin tools> DNS >Zone properties.
> What are the properties of DNS server?
INTERFACES, FORWARDERS, ADVANCED, ROUTINGS, SECURITY,
MONITORING, LOGGING, DEBUG LOGGING.
> Properties of a Zone ?
General, SOA, NAMESERVER, WINS, Security, and ZONE Transfer.
> What is scavenging?
Finding and deleting unwanted records.
> What are SRV records?
SRV are the service records, there are 6 service records. They are useful for
locating the services.
> What are the types of SRV records?
MSDCS:Contains DCs information.
TCP:Contains Global Catalog, Kerberos & LDAP information.
UDP:Contains Sites information.
Sites:Contains Sites information.
Domain DNS Zone:Conations domain?s DNS specific information.
Forest DNS zone:Contains Forest?s Specific Information.
> Where does a Host File Reside?
c:\windows\system32\drivers\etc.
> What is SOA?
Start of Authority: useful when a zone starts. Provides the zone startup
information.
> What is a query?
A request made by the DNS client to provide the name server information.
> What are the diff. types of Queries?
Recursion, iteration.
> Tools for troubleshooting DNS?
DNS Console, NSLOOKUP, DNSCMD, IPCONFIG, Logs.
> What is WINS server? where we use WINS server? difference
between DNS and WINS?
WINS is windows internet name service used to resolve the
NetBIOS(computer name)name to IP address.This is proprietary for
Windows.You can use in LAN.DNS is a Domain Naming System, which
resolves Host names to IP addresses. It uses fully qualified domain names.
DNS is an Internet standard used to resolve host names.
> What is new in Windows Server 2003 regarding the DNS
management?
When DC promotion occurs with an existing forest, the Active Directory
Installation Wizard contacts an existing DC to update the directory and
replicate from the DC the required portions of the directory.
If the wizard fails to locate a DC, it performs debugging and reports what
caused the failure and how to fix the problem. In order to be located on a
network, every DC must register in DNS DC locator DNS records. The Active
Directory Installation Wizard verifies a proper configuration of the DNS
infrastructure. All DNS configuration debugging and reporting activity is done
with the Active Directory Installation Wizard.
> SOA records must be included in every zone. What are they used
for?
SOA records contain a TTL value, used by default in all resource records in
the zone. SOA records contain the e-mail address of the person who is
responsible for maintaining the zone. SOA records contain the current serial
number of the zone, which is used in zone transfers.
By default, if the name is not found in the cache or local hosts file, what is
the first step the client takes to resolve the FQDN name into an IP address?
Performs a recursive search through the primary DNS server based on the
network interface configuration.
> How do I clear the DNS cache on the DNS server?
Go to cmd prompt and type ipconfig /flushdns .
> What is the main purpose of SRV records?
SRV records are used in locating hosts that provide certain network services.
> Before installing your first domain controller in the network, you
installed a DNS server and created a zone, naming it as you would
name your AD domain. However, after the installation of the domain
controller, you are unable to locate infrastructure SRV records
anywhere in the zone. What is the most likely cause of this failure?
The zone you created was not configured to allow dynamic updates. The
local interface on the DNS server was not configured to allow dynamic
updates.
> What is the "." zone in my forward lookup zone?
This setting designates the Windows 2000 or Windows Server 2003 DNS
server to be a root hint server and is usually deleted. If you do not delete
this setting, you may not be able to perform external name resolution to the
root hint servers on the Internet.
> Do I need to configure forwarders in DNS?
No. By default, Windows 2000 DNS uses the root hint servers on the
Internet; however, you can configure forwarders to send DNS queries
directly to your ISP's DNS server or other DNS servers. Most of the time,
when you configure forwarders, DNS performance and efficiency increases,
but this configuration can also introduce a point of failure if the forwarding
DNS server is experiencing problems.
The root hint server can provide a level of redundancy in exchange for
slightly increased DNS traffic on your Internet connection. Windows Server
2003 DNS will query root hints servers if it cannot query the forwarders.
> Should I point the other Windows 2000-based and Windows
Server 2003-based computers on my LAN to my ISP's DNS servers?
No. If a Windows 2000-based or Windows Server 2003-based server or
workstation does not find the domain controller in DNS, you may experience
issues joining the domain or logging on to the domain. A Windows 2000-
based or Windows Server 2003-based computer's preferred DNS setting
should point to the Windows 2000 or Windows Server 2003 domain
controller running DNS.
If you are using DHCP, make sure that you view scope option #15 for the
correct DNS server settings for your LAN.
> Do I need to point computers that are running Windows NT 4.0 or
Microsoft Windows 95, Microsoft Windows 98, or Microsoft Windows
98 Second Edition to the Windows 2000 or Windows Server 2003
DNS server?
Legacy operating systems continue to use NetBIOS for name resolution to
find a domain controller; however it is recommended that you point all
computers to the Windows 2000 or Windows Server 2003 DNS server for
name resolution.
> What if my Windows 2000 or Windows Server 2003 DNS server is
behind a proxy server or firewall?
If you are able to query the ISP's DNS servers from behind the proxy server
or firewall, Windows 2000 and Windows Server 2003 DNS server is able to
query the root hint servers. UDP and TCP Port 53 should be open on the
proxy server or firewall.
> What should I do if the domain controller points to itself for DNS,
but the SRV records still do not appear in the zone?
Check for a disjointed namespace, and then run Netdiag.exe /fix.
You must install Support Tools from the Windows 2000 Server or Windows
Server 2003 CD-ROM to run Netdiag.exe.
> How do I set up DNS for a child domain?
To set up DNS for a child domain, create a delegation record on the parent
DNS server for the child DNS server. Create a secondary zone on the child
DNS server that transfers the parent zone from the parent DNS server.
> What are Tools for troubleshooting of DNS?
DNS Console, NSLOOKUP, DNSCMD, IPCONFIG, DNS Logs.
Q: What is Active Directory?
A: Active Directory provides a centralised control for network administration and
security. Server computers configured with Active Directory are known as domain
controllers. Active Directory stores all information and settings for a deployment in a
central database, and allows administrators to assign policies and deploy and update
software.
Q: What is a Domain?
A: A domain is defined as a logical group of network objects (computers, users,
devices) that share the same Active Directory database. A tree can have multiple
domains.
Q: What is Domain Controller?
A: A domain controller (DC) or network domain controller is a Windows-based computer
system that is used for storing user account data in a central database. It is the
centrepiece of the Windows Active Directory service that authenticates users, stores
user account information and enforces security policy for a Windows domain.
A domain controller allows system administrators to grant or deny users access to
system resources, such as printers, documents, folders, network locations, etc., via a
single username and password.
Q: What is Group Policy?
A: Group Policy allows you to implement specific configurations for users and
computers. Group Policy settings are contained in Group Policy objects (GPOs), which
are linked to the following Active Directory service containers: sites, domains, or
organizational units (OUs).
Q: What are GPOs (Group Policy Objects)?
A: A Group Policy Object (GPO) is a collection of settings that control the working
environment of user accounts and computer accounts. GPOs define registry-based
policies, security options, software installation and maintenance options, script options,
and folder redirection options.
There are two kinds of Group Policy objects:
Local Group Policy objects are stored on individual computers.
Nonlocal Group Policy objects, which are stored on a domain controller, are available
only in an Active Directory environment.
Q: What is LDAP?
A: LDAP (Light-Weight Directory Access Protocol) determines how an object in an
Active Directory should be named. LDAP is the industry standard directory access
protocol, making Active Directory widely accessible to management and query
applications. Active Directory supports LDAPv2 and LDAPv3.
Q: Where is the AD database stored?
A: The AD database is stored in C:\Windows\NTDS\NTDS.DIT.
Q: What is the SYSVOL folder?
A: The SYSVOL folder stores the server copy of the domain’s public files that must be
shared for common access and replication throughout a domain.
All AD databases are stored in a SYSVOL folder and it’s only created in an NTFS
partition. The Active Directory Database is stored in the %SYSTEM ROOT%NDTS
folder.
Q: What is Garbage collection?
A: Garbage collection is the online defragmentation of the Active Directory which
happens every 12 hours.
Q: When do we use WDS?
A: Windows Deployment Services is a server role used to deploy Windows operating
systems remotely. WDS is mainly used for network-based OS installations to set up
new computers.
Q: What is DNS and which port number is used by DNS?
A: The Domain Name System (DNS) is used to resolve human-readable hostnames like
www.intenseschool.com into machine-readable IP addresses like 69.143.201.22.
DNS servers use UDP port 53 but DNS queries can also use TCP port 53 if the former
is not accepted.
Q: What are main Email Servers and which are their ports?
A: Email servers can be of two types:
Incoming Mail Server (POP3, IMAP, HTTP)
The incoming mail server is the server associated with an email address account. There
cannot be more than one incoming mail server for an email account. In order to
download your emails, you must have the correct settings configured in your email client
program.
Outgoing Mail Server (SMTP)
Most outgoing mail servers use SMTP (Simple Mail Transfer Protocol) for sending
emails. The outgoing mail server can belong to your ISP or to the server where you
setup your email account.
The main email ports are:
POP3 – port 110
IMAP – port 143
SMTP – port 25
HTTP – port 80
Secure SMTP (SSMTP) – port 465
Secure IMAP (IMAP4-SSL) – port 585
IMAP4 over SSL (IMAPS) – port 993
Secure POP3 (SSL-POP) – port 995
Q: What do Forests, Trees, and Domains mean?
A: Forests, trees, and domains are the logical divisions in an Active Directory network.
A domain is defined as a logical group of network objects (computers, users, devices)
that share the same active directory database.
A tree is a collection of one or more domains and domain trees in a contiguous
namespace linked in a transitive trust hierarchy.
At the top of the structure is the forest. A forest is a collection of trees that share a
common global catalog, directory schema, logical structure, and directory configuration.
The forest represents the security boundary within which users, computers, groups, and
other objects are accessible.
Q: Why do we use DHCP?
A: Dynamic Host Configuration Protocol assigns dynamic IP addresses to network
devices allowing them to have a different IP address each time they are connected to
the network.
Q: What are Lingering Objects?
A: A lingering object is a deleted AD object that still remains on the restored domain
controller in its local copy of Active Directory. They can occur when changes are made
to directories after system backups are created.
When restoring a backup file, Active Directory generally requires that the backup file be
no more than 180 days old. This can happen if, after the backup was made, the object
was deleted on another DC more than 180 days ago.
Q: How can we remove Lingering Objects?
A: Windows Server 2003 and 2008 have the ability to manually remove lingering objects
using the console utility command REPADMIN.EXE.
Q: Why should you not restore a DC that was backed up 6 months ago?
A: When restoring a backup file, Active Directory generally requires that the backup file
be no more than 180 days old. If you attempt to restore a backup that is expired, you
may face problems due to lingering objects.
Q: How do you backup AD?
A: Backing up Active Directory is essential to maintain the proper health of the AD
database.
Windows Server 2003
You can backup Active Directory by using the NTBACKUP tool that comes built-in with
Windows Server 2003 or use any 3rd-party tool that supports this feature.
Windows Server 2008
In Server 2008, there isn’t an option to backup the System State data through the
normal backup utility. We need to use the command line to backup Active Directory.
1. Open up your command prompt by clicking Start, typing “cmd” and then hit Enter.
2. In your command prompt, type “wbadmin start systemstatebackup -backuptarget:e:”
and press Enter.
3. Input “y” and press Enter to start the backup process.
When the backup process has finished you should get a message that the backup
completed successfully. If it did not complete properly you will need to troubleshoot.
The questions above are very tricky and important from the standpoint of clearing any
interview for a System Administrator (Microsoft) position. It is not possible for anyone to
list every possible question, but you can get more frequently asked interview questions
for System/Server Administrator (Microsoft) Jobsfrom thedownload link posted here. If you
find any difficulty in answering any questions, ask me below @ the Comments section.
DHCP
What is dhcp?
Dynamic Host Configuration Protocol (DHCP) is a network protocol that enables a server
to automatically assign an IP address to a computer from a defined range of numbers
(i.e., a scope) configured for a given network.
What is the dhcp process for client machine?
1. A user turns on a computer with a DHCP client.
2. The client computer sends a broadcast request (called a DISCOVER or
DHCPDISCOVER), looking for a DHCP server to answer.
3. The router directs the DISCOVER packet to the correct DHCP server.
4. The server receives the DISCOVER packet. Based on availability and usage
policies set on the server, the server determines an appropriate address (if any) to give
to the client. The server then temporarily reserves that address for the client and sends
back to the client an OFFER (or DHCPOFFER) packet, with that address information.
The server also configures the client’s DNS servers, WINS servers, NTP servers, and
sometimes other services as well.
5. The client sends a REQUEST (or DHCPREQUEST) packet, letting the server
know that it intends to use the address.
6. The server sends an ACK (or DHCPACK) packet, confirming that the client has
a been given a lease on the address for a server-specified period of time.
What is dhcp scope ?
DHCP scopes are used to define ranges of addresses from which a DHCP server can
assign IP addresses to clients.
Types of scopes in windows dhcp ?
Normal Scope – Allows A, B and C Class IP address ranges to be specified including
subnet masks, exclusions and reservations. Each normal scope defined must exist
within its own subnet.
Multicast Scope – Used to assign IP address ranges for Class D networks. Multicast
scopes do not have subnet masks, reservation or other TCP/IP options. Multicast scope
address ranges require that a Time To Live (TTL) value be specified (essentially the
number of routers a packet can pass through on the way to its destination).
Super scope – Essentially a collection of scopes grouped together such that they can
be enabled and disabled as a single entity.
What is Authorizing DHCP Servers in Active Directory ?
If a DHCP server is to operate within an Active Directory domain (and is not running
on a domain controller) it must first be authorized. This can be achieved either as part
of the DHCP Server role installation, or subsequently using 2 either DHCP console or at
the command prompt using the netsh tool. If the DHCP server was not authorized
during installation, invoke the DHCP console (Start -> All Programs -> Administrative
Tools -> DHCP), right click on the DHCP to be authorized and select Authorize. To
achieve the same result from the command prompt, enter the following command:
netsh dhcp server serverID initiate auth In the above command syntax, serverID is
replaced by the IP address or full UNC name of system on which the DHCP server is
installed.
Q: – What is DHCP?
DHCP stands for “Dynamic Host Configuration Protocol”.
Q: – How can I prevent unauthorized laptops from using a network
that uses DHCP for dynamic addressing?
This would have to be done using a mechanism other than DHCP. DHCP does
not prevent other clients from using the addresses it is set to hand out nor
can it distinguish between a computer‟s permanent MAC address and one set
by the computer‟s user. DHCP can impose no restrictions on what IP address
can use a particular port nor control the IP address used by any client.
Q: – Can a BOOTP client boot from a DHCP server?
Only if the DHCP server is specifically written to also handle BOOTP queries.
Q: – What is DHCP’s purpose?
DHCP‟s purpose is to enable individual computers on an IP network to
extract their configurations from a server (the „DHCP server‟) or servers, in
particular, servers that have no exact information about the individual
computers until they request the information. The overall purpose of this is
to reduce the work necessary to administer a large IP network. The most
significant piece of information distributed in this manner is the IP address.
Q: – How can I prevent unauthorized laptops from using a network
that uses DHCP for dynamic addressing?
This would have to be done using a mechanism other than DHCP. DHCP does
not prevent other clients from using the addresses it is set to hand out nor
can it distinguish between a computer‟s permanent MAC address and one set
by the computer‟s user. DHCP can impose no restrictions on what IP address
can use a particular port nor control the IP address used by any client.
Q: – Can a BOOTP client boot from a DHCP server?
Only if the DHCP server is specifically written to also handle BOOTP queries.
Q: – Can DHCP work with Apple Talk or IPX?
No, it is too tied to IP. Furthermore, they don‟t need it since they have
always had automated mechanisms for assigning their own network
addresses.
Q: – What is a DHCP lease?
A DHCP lease is the amount of time that the DHCP server grants to the
DHCP client permission to use a particular IP address. A typical server allows
its administrator to set the lease time.
Q: – What is DHCP Spoofing?
Ascend Pipeline ISDN routers (which attach Ethernets to ISDN lines)
incorporate a feature that Ascend calls “DHCP spoofing” which is essentially
a tiny server implementation that hands an IP address to a connecting
Windows 95 computer, with the intention of giving it an IP number during its
connection process.
Q: – How long should a lease be?
A very relevant factor is that the client starts trying to renew the lease when
it is halfway through: thus, for example, with a 4 day lease, the client which
has lost access to its DHCP server has 2 days from when it first tries to
renew the lease until the lease expires and the client must stop using the
network. During a 2- day outage, new users cannot get new leases, but no
lease will expire for any computer turned on at the time that the outage
commences. Another factor is that the longer the lease the longer time it
takes for client configuration changes controlled by DHCP to propogate.
Q: – Is a DHCP client “supposed to” be able to use a BOOTP server?
The RFC on such interoperability (1534) is clear: “A DHCP client MAY use a
reply from a BOOTP server if the configuration returned from the BOOTP
server is acceptable to the DHCP client.” (section 3). The word “MAY”
indicates such support, however useful, is left as an option.
Q: – What is a Client ID?
What is termed the Client ID for the purposes of the DHCP protocol is
whatever is used by the protocol to identify the client computer. By default,
DHCP implementations typically employ the client‟s MAC address for this
purpose, but the DHCP protocol allows other options. Some DHCP
implementations have a setup option to specify the client ID you want. One
alternative to the MAC address is simply a character string of your choice. In
any case, in order for DHCP to function, you must be certain that no other
client is using the client ID you choose, and you must be sure the DHCP
server will accept it.
Q: – How can I relay DHCP if my router does not support it?
A server on a net(subnet) can relay DHCP or BOOTP for that net. Microsoft
has software to make Windows NT do this.
Q: – Is a DHCP server “supposed to” be able to support a BOOTP
client?
The RFC on such interoperability (1534) is clear: “In summary, a DHCP
server:
… MAY support BOOTP clients,” (section 2). The word “MAY” indicates such
support, however useful, is left as an option.
A source of confusion on this point is the following statement in section 1.5
of RFC 1541: “DHCP must provide service to existing BOOTP clients.”
However, this statement is one in a list of “general design goals for DHCP”,
i.e. what the
designers of the DHCP protocol set as their own goals. It is not in a list of
requirements for DHCP servers.
Q: – Can DHCP support statically defined addresses?
Yes. At least there is nothing in the protocol to preclude this and one expects
it to be a feature of any DHCP server. This is really a server matter and the
client should work either way. The RFC refers to this as manual allocation.
Q: – What is a MAC address?
A MAC address (also called an Ethernet address or an IEEE MAC address) is
a number (typically written as twelve hexadecimal digits, 0 through 9 and A
through F, or as six hexadecimal numbers separated by periods or colons,
i.e. 0080002012ef, 0:80:0:2:20:ef) which uniquely identifes a computer that
has an Ethernet interface. Unlike the IP number, it includes no indication of
where your computer is located. In DHCP‟s typical use, the server uses a
requesting computer‟s MAC address to uniquely identify it.
Q: – Can a DHCP server back up another DHCP server?
You can have two or more servers handing out leases for different
addresses. If each has a dynamic pool accessible to the same clients, then
even if one server is down, one of those clients can lease an address from
the other server. However, without communication between the two servers
to share their information on current leases, when one server is down, any
client with a lease from it will not be able to renew their lease with the other
server. Such communication is the purpose of the “server to server protocol”
(see next question). It is possible that some server vendors have addressed
this issue with their own proprietary server-to-server communication.
Q: – What protocol and port does DHCP use?
DHCP, like BOOTP runs over UDP, utilizing ports 67 and 68.
Troubleshooting
1) Explain what is Windows Server?
Window server is a series of server operating system developed by Microsoft
Corporation.
2) Explain in windows DNS server what is Primary, Secondary and Stub zone?
In windows DNS server,
Primary Zone: In this, the file is saved as normal text file with filename (.dns).
Secondary Zone: It maintains a read-only copy of zone database on another DNS
server. Also, it acts as a back-up server to the primary server by providing fault tolerance
and load balancing
Stub Zone: It consists of a copy of name server and SOA records which is used for
reducing the DNS search orders.
Explain how you can set up remote installation procedure without giving access to user?
To do that, you have to go to,
gponameà User Configuration à Windows Settings à Remote Installation Services à
Choice Options
Mention how many types of queries DNS does?
The types of queries DNS does are
Iterative Query
Recursive Query
Explain what is the primary function of the domain controller?
Primary function of the domain controller is to validate users to the networks, it
also provide a catalog of Active Directory Objects.
9) What information is required when TCP/IP is configured on Window Server?
To configure a TCP/PI client for an IPv4 client, you have to provide the IP
address and the subnet mask.
Explain what is LDAP?
To look up for the information from the server, e-mail and another program follows or
uses the internet protocol. This protocol is referred as LDAP or Lightweight Directory
Access Protocol.
13) Explain what is SYSVOL folder?
It is a set of files and folders that is stored on the local hard disk of each domain
controller in a domain and are replicated by the FRS ( File Replication Service). These
files contain group or user policy information.
Explain what is INODE?
INODE holds the metadata of files; INODE is a pointer to a block on the disk, and it is
unique.
In simple words, it is a unique number allocated to a file in UNIX-like OS.
16) Explain what is RAID in Windows Server?
For storing same data at a different place RAID or Redundant Array of Independent
Disks strategy is used. It is a strategy for building fault tolerance and increase the
storage capacity. On separate drives it allows you to combine one or more volumes so
that they are accessed by a single drive letter
17) Explain what is the purpose of deploying local DNS servers?
A local DNS server provides the local mapping of fully qualified domain names to IP
addresses. To resolve remote requests related to the domains names on your network,
local DNS servers can provide record information to remote DNS servers.
18) To check TCP/IP configurations and IP connectivity, what are the two command line
utilities that can be used?
Ipconfig: To check the computer’s IP configuration, command ipconfig can be used and
also it can be used to renew the client’s IP address if it is provided by a DHCP server.
Ping: To check the connection between the local computer and any of the other
computer device on the network Ping command is used
19) Explain if it is possible to connect Active Directory to other 3rd
party Directory
services?
Yes, you can connect other vendors directory services with Microsoft version. By using
dirXML or LDAP to connect to other directories.
IP Addressing
1. Explain range of TCP/IP classes
Answer :
CLASS A = 1 to 126
CLASS B = 128 to 191
CLASS C = 192 to 223
CLASS D = 224 to 239 (Multicasting)
CLASS E = 240 to 255 (Research)
2. What are Pvt. IP address ?
Answer : Pvt. IP are IPs which are not used in Internet or which are not
routable in
Internet. They are also called as non-routable IP's. Class A = 10.0.0.0 to
10.255.255.255
Class B = 172.16.0.0 to 172.31.255.255
Class C = 192.168.0.0. to 192.168.255.255
3. What is function of Router ?
Answer : Router is a device or PC which is used to connect two or more IP
networks.
4. What is Default Gateway :
Answer : Default gateway is the address of router.
5. What is Subnet Mask ?
Answer : Subnet mask is used to differentiate Network ID and Host ID from
a given IP
address. The default subnet mask are as under
Class A = 255.0.0.0
Class B = 255.255.0.0
Class C = 255.255.255.0
6. What is Loopback address ?
Answer : The loopback address is 127.0.0.1. This address is used to check
local TCP/IP
suite or local machine.
7. What protocol is used by PING ?
Answer : Ping uses ICMP(Internet Control Management Protocol)
8. What is used of Tracert ?
Answer : Tracert is a to find path information between source and
desitnation. It show no.
of hops between source and desitination. Tracert also uses ICMP protocol.
9. Difference between NetBEUI and TCP/IP
Answer :
TCP/IP NetBEUI
a. industry standard Microsoft propertiery
b. IP address NO addressing
c. supports routing Non routable
d. Large network small network
e. more confiugration no configuration
10. What is full form of PING ?
Answer : Packet Internet Network Gopher
BASICS OF NETWORKING
1. Difference between Switch and Hub
Switch HUB
a. Works at layer 2 works at layer 1
b. Uses MAC address for packet uses broadcast for packet forwarding
forwarding
c. Does not required CSMA/CD requires CSMA/CD
d. Faster than HUB Slower than Switch
e. Full-duplex Half-duplex
f. high throughput low throughput
2. Explain AT&T color code for straight cable and cross cable
Answer :
Orange/white
orange
green/white
3. what is bandwidth of of CAT5 cable
Answer : 100 Mbps
4. What is the recommanded CAT5 cable length between switch and
PC ?
Answer : 100 meters
5. When to use cross cable and straight cable
Answer :
Similar device = cross cable
eg. switch to switch
PC to PC, Hub to HUB, Switch to HUB,PC to router, router to router
Unsimilar device = straight cable
eg. PC to switch, PC to HUB,Router to Switch
6. Which pins are used in CAT5 cables
Answer : pin no. 1,2,3,6
pin 1 = tx +
pin 2 = tx -
pin 3 = rx +
pin 6 = rx -
7. difference between domain and workgroup
Answer :
Domain Workgroup
a. centralized network model decentralized network
b. Domain is controlled by DC No centrailzed control
c. Centralised login Local login
d. centrailsed user database local user databased
e. Easy and centrailsed management NA
f. good for large network good for small network
8. Different types of LAN topologies
a. Bus topology = 10base2 (Thinnet)
= 10base5 (Thicknet)
b. Star topology = 10baseT (ethernet, 10 mbps)
= 100baseTx (fastethernet, 100 mbps)
= 100baseFX (fastethernet with Fibre)
= 1000baseTX (gigabit ethernet, 1000 mbps)
= 1000basefx (gigabit ethernet with fibre)
c. WAN toplogies = PSTN (Public switched telephone network)
= ISDN (Integrated switched digital network)
= Frame Relay
= Leased Line
= DSL (Digital subscriber line)
= ATM (Async Transfer Mode)
9. Explain in short about all 7 layers of OSI
Application layer = user interface and application
Presentation layer = Data conversion and transformation
session layer = keep data of diff. application seperately
transport layer = end to end connectivity using port numbers.
network layer = logical addressing like IP address.
Data link layer = Physical addressing like MAC address.
Physical layer = Physical transmission of data using 0's and 1's.
DHCP, DNS and WINS
1. What is DNS ?
Answer : It is used to resolve FQDN to IP address.
2. Types of Zone in DNS ?
Answer : Forward Lookup - it is used to resolve FQDN to IP
Reverse lookup - it is used to resolve IP to FQDN
3. Types of DNS Zone ?
Primary Zone :
Secondary Zone :
AD integrated Zone :
Stub Zone :
4. what is NSlookup ?
Answer : it is a tool used troubleshoot DNS related issues.
5 What is DHCP ?
Answer: DHCP is used to automatically provide IP address to client
computers.
6. Explain DHCP 4 packets.
Discover = client sends request for IP.
Offer = DHCP server send and Offer with IP address.
Request = if clients accepts the IP it sends a request to DHCP.
Ack = DHCP server sends ack for the same.
7. What is client reservation in DHCP ?
Answer : to reserve a specific IP for a specific machine or host.
8. What is WINS ?
Answer : It is used to resolve NetBIOS Computer name to IP address.
9. Which port number DHCP uses?
Answer : DHCP uses UDP port number 67 and 68.
BASIC NETWORKING CONCEPTS
1) What is Web Server ?
Answer : Web server is a server or application server which host or stores
websites.
Every web site should have a name like www.vision.com and IP address. Eg.
IIS, Apache
server, etc.
2) What is mail server ?
Answer : Mail server is a software which maintains user mailboxes. eg :
Exchange server
, Lotus domino, etc
3) What is mail client ?
Answer : A sofware used by client to access to mails stores on mail server.
using mail
client software you can send mail and receive mail. Eg : Microsoft Outlook,
Outlook
Express, Lotus notes, etc.
4) What is Proxy server ?
Answer : It is a software used for sharing of internet connection. Eg.
Wingate, Winproxy,
Analog proxy, etc.
5) Port numbers for various application and services
There are total 65536 ports available. Below are the list of some well-known
ports.
LDAP : 389,Kerberos : 88,DNS : 53,SMTP : 25,POP3 : 110,Telnet :
23,NNTP : 119,IMAP : 143
RPC : 135,HTTP : 80,HTTPS / SSL : 443,FTP : 21
6) What is firewall ?
Answer : It is a software used to provide security to your network by not
allowing
unauthorized access to your Internal network from External users. Eg : PIX
firewall,
Checkpoint firewall, etc.
1) Which protocol is used by ADS for time sync. between PC's?
Answer : SNTP (Simple network time protocol)
2) What is RPC protocol ?
Answer : RPC stands for Remote Procedure Call. It uses port number 135.
RPC is an
inter-process communication technique that allows client and server
software to
communicate.
3) What is COM ?
Answer : Component Object Model (COM) is Microsoft's object-oriented
programming
model that defines how objects interact within a single application or
between
applications.
4) What is SNMP ?
Answer : SNMP stands for Simple Network Management Protocol). This
protocol is
used to monitor and manage network devices like Switches, Routers,
Servers, etc. SNMP
uses port UDP port number 161 and 162.
1. What is the length of ipv6? Important Interview networking
questions
Ans:- 128 bit
2. Where is the hub specified in the OSI model?
Ans:- Physical layer
3. Difference between TCP and UDP?
Ans:a) TCP is Transmission control protocol.
b) It is connection oriented.
c) Reliable
d) Uses checksum to detect errors.
UDP-
a) UDP is user datagram protocol.
b) It is connectionless.
c) Non reliable.
d) No acknowledgement.
4. What is a gateway? Networking questions
Ans:-Gateway is a device that connects two dissimilar networks. It is in
application layer.
5. Name the two routing protocols?
Ans:-RIP & OSPF (intra domain routing protocol)
6. What is the advantage of OSPF protocol?
Ans:-OSPF(open shortest path first) based on link state routing protocol. It
handle routing efficiently and in timely manner.
7. What are the different layers in the OSI model? Basic Networking
questions
Ans:- Different layers of OSI model:
8. What is a firewall? Basic Networking questions
Ans:-Firewall is a network that protects internet from unauthorized access.
It is need for every computer system. proxy firewall is a type of firewall.
9. Difference between intra domain and inter domain routing
protocol?
Ans:-Routing within an autonomous system is referred as intra domain
routing protocol and routing between an autonomous system is called as
inter domain routing protocol.
10. Name the ports used by FTP protocol?
Ans:- FTP is file transfer protocol. It copies file and transfer from one
system to another port no is 20 for connection and port 21 is for data
transfer.
11. Define Network?
Ans:- A network is a collection of devices which are connected by means of
physical media links or it is connection of two or more nodes in a recursive
manner by a physical link.
Basic Networking interview questions
12. What is a Link? basic networking questions
Ans:- Link is a physical medium such as coaxial cable or optical fibre that
connects two or more computers directly which form a network.
13. What is a node?
Ans:- Links are physical medium that connects two or more computers
directly and the computer it connects is called as nodes.
14. State the advantages of Distributed Processing?
Ans:- The advantages are:-
a. Security/Encapsulation
b. Distributed database
c. Faster Problem solving
d. Security by means of redundancy
e. Collaborative Processing
15. Mention the factors by which a network performance is affected?
Ans:-
a. No. of Users
b. Transmission medium type
c. Hardware
d. Software
16. Name the factors that affect the reliability of the network? basic
networking questions
a. Failure frequency
b. Network Recovery time after a failure
17. What are the key elements of protocols?
Ans:- The key elements of protocols are as follows:-
a. Syntax
It refers to the format of the data, the order in which they are represented.
b. Semantics
It refers to the meaning of each section of bits.
c. Timing
Timing refers to: When data should be sent and how fast.
18. Mention the key design issues of a computer Network?
Ans:- The Key design issues are as follows:-
a. Connectivity of the network
b. Cheap resource Sharing
c. Common Services will have support
d. Performance of the network
19. Define Bandwidth and Latency? basic networking questions
Ans:- Performance of network is measured in Bandwidth called throughput
and Latency called Delay. Network bandwidth is the number of bits which
can be transmitted over the network over a certain period of time. Latency
refers to the time taken by a message to travel from one end of network to
another. It is strictly measured in terms of time.
20. Describe the situation when a switch is said to be congested?
Ans:- It is possible that a switch for an extended period of time can receives
packets faster than the shared link can accommodate and stores in its
memory, then the switch will eventually run out of buffer space, and some
packets has to be dropped & is said to be congested state.
21. Describe semantic gap?
Ans:- A useful channel includes both two things that is to understand the
applications requirements and recognize underlying technology limitations.
The gap between what applications expects or desires and what the
underlying technology can provide or give is called semantic gap.
22. Which layers are user support layers?
Ans:- User support layers are as follows:-
a. Session layer
b. Presentation layer
c. Application layer
23. What is Error Detection? What are the methods?
Ans:- During transmission data can get corrupted. In order to have a
reliable communication errors must be deducted and corrected. Error
Detection uses the concept of redundancy by means of which it adds extra
bits to detect errors at the destination. The error detection methods are as
follows:-
a. Vertical Redundancy Check
b. Longitudinal Redundancy Check
c. Cyclic Redundancy Check
d. Checksum
24. What are Data Words?
Ans:- In block coding, message is divided into blocks, each of k bits, called
data words. The same data word is always encoded as the same code word.
25. What is Framing?
Ans:- The work of framing in the data link layer is to separate a message
from one source to a destination, or from other messages to other
destinations, by adding a sender & destination address. The destination
address is the address of the packet where it has to go and the sender
address helps the recipient acknowledge the receipt.
26. What is Error Control ?
Ans:- Error detection and error correction is called as error control. If any
frame is lost or damaged in transmission than the receiver inform it to that
particular sender and ask to retransmit those frames by the sender. In the
data link layer, error control refers primarily to methods of error detection
and retransmission.
27. What is utility of sequence number in Reliable Transmission?
Ans:- The protocol specifies that frames numbering has to be done using
sequence numbers. A field is added to the data frame section in order to
hold the sequence number of that frame. As we want to minimize the frame
size which will provide unambiguous communication. The sequence numbers
can wrap around.
28. What is MAC address?
Ans:- Media Access Control (MAC) layer is the device address in the
network architecture. MAC address is unique and is usually stored in ROM on
the network adapter card.
29. What is the difference between TFTP and FTP application layer
protocols?
Ans:- In order to obtain files from a remote host trivial file transfer protocol
is used but it does not provide reliability or security. The File Transfer
Protocol (FTP) is the standard mechanism which is by TCP / IP to copy a file
from one host to another. TCP offer services that are reliable and
secure. Two connections are established between the hosts, one for data
transfer and another for control information.
30. What are major types of networks explain it?
Ans:- Two major types-Server-based network: In this there is centralized
control of network resources and it depends on server computers for security
as well as network administration
Peer-to-peer network: In this the computers can act as both sharing
resources servers as well as clients using the resources.
Cloud Computing
What are the different layers of cloud computing?
Cloud computing consists of 3 layers in the hierarchy and these are as follows:
1. Infrastructure as a Service (IaaS) provides cloud infrastructure in terms of hardware like
memory, processor speed etc.
2. Platform as a Service (PaaS) provides cloud application platform for the developers.
3. Software as a Service (SaaS) provides cloud applications which are used by the user
directly without installing anything on the system. The application remains on the cloud and
it can be saved and edited in there only.
What resources are provided by infrastructure as a service?
Infrastructure as a Service provides physical and virtual resources that are used to build a cloud.
Infrastructure deals with the complexities of maintaining and deploying of the services provided by
this layer. The infrastructure here is the servers, storage and other hardware systems.
How important is platform as a service?
Platform as a Service is an important layer in cloud architecture. It is built on the infrastructure
model, which provides resources like computers, storage and network. This layer includes
organizing and operate the resources provided by the below layer. It is also responsible to provide
complete virtualization of the infrastructure layer to make it look like a single server and keep it
hidden from the outside world.
What does software as a service provide?
Software as Service is another layer of cloud computing, which provides cloud applications like
google is doing, it is providing google docs for the user to save their documents on the cloud and
create as well. It provides the applications to be created on fly without adding or installing any
extra software component. It provides built in software to create wide varieties of applications and
documents and share it with other people online.
What are the different deployment models?
Cloud computing supports many deployment models and they are as follows:
• Private Cloud
Organizations choose to build there private cloud as to keep the strategic, operation and other
reasons to themselves and they feel more secure to do it. It is a complete platform which is fully
functional and can be owned, operated and restricted to only an organization or an industry. More
organizations have moved to private clouds due to security concerns. Virtual private cloud is
being used that operate by a hosting company.
• Public Cloud
These are the platforms which are public means open to the people for use and deployment. For
example, google, amazon etc. They focus on a few layers like cloud application, infrastructure
providing and providing platform markets.
• Hybrid Clouds
It is the combination of public and private cloud. It is the most robust approach to implement cloud
architecture as it includes the functionalities and features of both the worlds. It allows
organizations to create their own cloud and allow them to give the control over to someone else
as well.
What are the different datacenters deployed for this?
Cloud computing is made up of various datacenters put together in a grid form. It consists of different
datacenters like:
• Containerized Datacenters
These are the traditional datacenters that allow high level of customization with servers, mainframe
and other resources. It requires planning, cooling, networking and power to access and work.
• Low-Density Datacenters
These datacenters are optimized to give high performance. In these datacenters the space constraint
is being removed and there is an increased density. It has a drawback that with high density the heat
issue also creeps in. These datacenters are very much suitable to develop the cloud infrastructure.
What is the security aspects provided with cloud?
Security is one of the major aspects which come with any application and service used by
the user. Companies or organizations remain much more concerned with the security
provided with the cloud.
There are many levels of security which has to be provided within cloud environment such
as:
• Identity management: it authorizes the application service or hardware component to be
used by authorized users.
• Access control: permissions has to be provided to the users so that they can control the
access of other users who are entering the in the cloud environment.
• Authorization and authentication: provision should be made to allow the authorized and
authenticated people only to access and change the applications and data.
TCP/IP
Description of different TCP/IP protocols
Layer 1: Host-to-network Layer
1. Lowest layer of the all. 2. Protocol is used to connect to the host, so that the packets can be sent over it. 3. Varies from host to host and network to network.
Layer 2: Internet layer
1. Selection of a packet switching network which is based on a connectionless internetwork layer is called a internet layer.
2. It is the layer which holds the whole architecture together. 3. It helps the packet to travel independently to the destination. 4. Order in which packets are received is different from the way they are sent. 5. IP (Internet Protocol) is used in this layer.
Layer 3: Transport Layer
1. It decides if data transmission should be on parallel path or single path. 2. Functions such as multiplexing, segmenting or splitting on the data is done by
transport layer. 3. The applications can read and write to the transport layer. 4. Transport layer adds header information to the data. 5. Transport layer breaks the message (data) into small units so that they are handled
more efficiently by the network layer. 6. Transport layer also arrange the packets to be sent, in sequence.
Layer 4: Application Layer
The TCP/IP specifications described a lot of applications that were at the top of the protocol stack. Some of them were TELNET, FTP, SMTP, DNS etc.
1. TELNET is a two-way communication protocol which allows connecting to a remote machine and run applications on it.
2. FTP(File Transfer Protocol) is a protocol, that allows File transfer amongst computer users connected over a network. It is reliable, simple and efficient.
3. SMTP(Simple Mail Transport Protocol) is a protocol, which is used to transport electronic mail between a source and destination, directed via a route.
4. DNS(Domain Name Server) resolves an IP address into a textual address for Hosts connected over a network.
Merits of TCP/IP model
1. It operated independently. 2. It is scalable. 3. Client/server architecture. 4. Supports a number of routing protocols. 5. Can be used to establish a connection between two computers.
Demerits of TCP/IP
1. In this, the transport layer does not guarantee delivery of packets. 2. The model cannot be used in any other application. 3. Replacing protocol is not easy. 4. It has not clearly separated its services, interfaces and protocols.
Wireless Network
Here are some benefits of an Ad-Hoc network are:- a) The possibilities with Ad-Hoc network are quite endless. b) Ad-Hoc networks are simple to set up. c) Ad-Hoc networks are inexpensive. d) Ad-Hoc networks are fast. Disadvantages of an Ad-Hoc network are as follows:- a) It is not able to get into the mainstream wired local area network. b) It needs more technology to support their reliability. c) As the network increases its speed slows down considerably. 2) In Infrastructure mode, network includes an access point when the wireless clients connect to an access point, which in turn bridges to a network. Infrastructure network can
pass information through a central information hub which can be both, hardware or software device on a computer. So under this devices in a wireless network are set up to communicate through an access point.
How do you secure a wireless network?
Key points for securing a wireless network are as follows:- a) Verify that your PC’s software firewall is turned on, and that Window’s file-sharing feature is off; it’s off by default in Window’s XP with Service Pack 2. b) Never send bank passwords, credit card numbers, confidential e-mail, or other sensitive data unless you’re sure you’re on secure site: Look for the lock icon in the bottom-right corner of your browser, as well as a URL in the address bar that begins with https. Such sites build in their own encryption. c) Always turn your Wi-Fi radio off when you're not at a hotspot: Hackers can use it to create peer-to-peer Wi-Fi connections with your computer and access it directly. d) For better security, consider signing up for a paid subscription to a hotspot network such as Boingo or T-Mobile. Both companies provide connection software that encrypts your sessions automatically.
How can you configure Wi-Fi network and what are Wi-Fi
Protocols?
1) Basically there are many standards of Wi-Fi in the industry but some popular of them are 802.11a, 802.11b, 802.11g/n. With the support of these Wi-Fi protocols we can communicate/interact among the devices at the speed of 5Ghz to 2.4Ghz dual band communication. 2) If we have Wi-Fi nic card so firstly we have to install their drivers and after installation if we have Wi-Fi access point then we can see the signal strength in the right corner below just open that and find the access point to connect, if access point is configured with the security, type the key to connect and enjoy the service. 3) Wi-Fi is technically referred to as the 802.11 protocol. Over time, Wi-Fi has improved, giving rise to different variations of the protocol. 802.11a – This version operates at 54Mbps. It is considered as the favorite wireless LAN protocol for IP telephony.
