Securely Extending RDS to the InternetHow to Internet-Enable your Applications

Greg Shields, MVPSenior Partner and Principal Technologist

www.ConcentratedTech.com

RDS: Not Just About Desktops Any More!

The Many Jobs of the RDS Administrator

• Server Administrator• Workstation Administrator

● Systems Babysitter…

• Application Administrator● Installing, managing, maintaining, patching…

• Security & Lockdown Administrator● Protect users from themselves and others…

• Workflow Administrator● Getting users to their applications…

NEW!

5 Ways to Deploy RemoteApps

RDP File Distribution● Create an RDP file and store it in a file server or distribute it to

users. Users double-click to launch app. RD Web Access

● Users double-click applications on web sites to launch. Local Desktop Installation

● RemoteApps are wrapped into MSI files, which are “installed” onto desktops.

Local Desktop Installation with Client Extension Re-association

● Same as above, but local client file extensions are modified to enable document invocation.

RemoteApp and Desktop Connection● Windows 7 RADC regularly synchronizes data from server to

populate desktop & Start Menu with configured apps.

#1 - RDP File Distribution

• In Server 2003, only “true” native way to distribute connections to Remote Desktops.

● Can also manually host RDP files on a web page.

• Superseded in 2008 by new technologies, however remains useful for…

● Users who want user-based customizability for RDP connections.

● Users who need portability for application connections, such as those who roam networks.

● Users who share/customize connections

• IMPORTANT: Currently the only way to deploy RemoteApp for Hyper-V applications!

#2 - RD Web Access

• Enabling an app in RDWA requires two clicks.● Provisioning and deprovisioning apps is ridiculously fast/easy.● Useful for users who use few applications that do not integrate

with each other.● Very useful for applications that rapidly change, change

versions, or require offline maintenance.

• Zero additional effort at the individual desktop.

#2 - RD Web Access

• R2 supports the “hiding” of apps.● Use perms and “User Assignment” to restrict app access.

• Limited to a single server out-of-the-box in 2008.● RD Session Broker creates RDS farm of similarly-configured

servers.● SharePoint web part integration can group dissimilar servers.

Non-trivial.

• R2 adds the ability to consolidate multiple RDSHs.• Does not support document invocation or local desktop

integration.

#2 - RD Web Access

Enabling or disabling access requires only a few mouse clicks in Server Manager.

#3 - Local Desktop Installation

• Wrapping RDP files into MSI files enables local desktop installation.

● RemoteApps launched from local Start Menu or desktop shortcut.

● Enhances RemoteApp “seamlessness”.

• MSI files must be installed onto each desktop.● Active Directory Software Installation through Group Policy● A systems management solution (SCCM)● Shoe leather.

• Removing applications once installed is complex with any mechanism.

● Non-trivial to change once implemented.

#3 - Local Desktop Installation

#4 - Client Extension Re-Association

• Client extension re-association is an optional part of local desktop installation.

● Modifies client extensions (.DOCX, .XLSX, etc.) to enable document invocation.

● Users maintain existing local desktop workflow by double-clicking documents.

● Highest degree of “seamlessness” possible with RDS and non-W7.

• Document Invocation!

#4 - Client Extension Re-association

Associate client extensions for this program with the

RemoteApp program

#4 - Client Extension Re-association

Extensions re-associate with

“Remote Desktop Connection”

#5 – RemoteApp & Desktop Connection

• If you have Windows 7 / 08R2, then you have RADC. No other OSs currently support RADC.

• RADC works functionally similar to Citrix XenApp Plug-in.

● Plug-in regularly checks server to download XML file.● XML file contains connection information about configured

RemoteApps and desktops● By default, client checks once per hour, so propagation can take

time.

Securing the User’s Connection

What You’ll Need

• Enabling Internet-grade security for RDS sessions requires a few extra components:

● RD Gateway Server● SSL Server certificate from Public CA● A firewall● Some holes in the firewall

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What You’ll Need

• Enabling Internet-grade security for RDS sessions requires a few extra components:

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dc.contoso.com

contoso.com

server1.contoso.comRemote Desktop

Gateway

server2.contoso.comRemote Desktop

Session Host

client1.myhome.com

443/TCP 3389/TCP

What You’ll Need

• Enabling Internet-grade security for RDS sessions requires a few extra components:

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dc.contoso.com

contoso.com

server1.contoso.comRemote Desktop

Gateway

server2.contoso.comRemote Desktop

Session Host

client1.myhome.com

443/TCP 3389/TCP

Wait a minute!

Anyone see problems here?

LIVE DRAW:RDG Architectures

Four RDG Architectures

Option #1: No DMZ. RDG in the LAN.

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Four RDG Architectures

Option #1: No DMZ. RDG in the LAN.Option #2: RDG in the DMZ. No internal AD exposure

for RDG.

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Four RDG Architectures

Option #1: No DMZ. RDG in the LAN.Option #2: RDG in the DMZ. No internal AD exposure

for RDG.Option #3: RDG in the DMZ. Internal AD is exposed to

RDG. Option #3a: Use internal DC. Open lots of ports. Option #3b: Internal RODC in the DMZ. Open lots of ports. Option #3c: Forest trust to DC in the DMZ.

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Four RDG Architectures

Option #1: No DMZ. RDG in the LAN.Option #2: RDG in the DMZ. No internal AD exposure

for RDG.Option #3: RDG in the DMZ. Internal AD is exposed to

RDG. Option #3a: Use internal DC. Open lots of ports. Option #3b: Internal RODC in the DMZ. Open lots of ports. Option #3c: Forest trust to DC in the DMZ.

Option #4: ISA in the DMZ. RDG in the LAN. Option #4 is Microsoft’s (and the industry’s) recommended

practice.

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The Vast Power of SSL Reverse Proxying!

An SSL Reverse Proxy is a device used to bridge external SSL connections to the inside. Inbound SSL connections are terminated at the proxy. Decrypts SSL communication. Inspects them for malicious code. (Optionally) Reconstructs them into a new SSL connection and

forwards traffic inside.

HTTPS – HTTPS or HTTPS – HTTP HTTPS – HTTPS is better for internal security. HTTPS – HTTP is better for performance.

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Installing the RDG

Four questions are required during installation.● Server authentication certificate. If you’ve correctly installed

your certificate to the local computer’s Personal Store, you will see that certificate listed in the box.

● RD Gateway User Groups. Groups which are allowed to connect to internal resources through this RDG server.

● RD CAP. Identifies mechanisms used for authenticating users to the RD Gateway server: Password or smart card.

● RD RAP. Identifies internal computers which can be accessed by users who enter through the RDG.

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SSL Certificates

• Server certificate attributes● Must be a computer certificate● Extended key usage must be for Server Authentication

(OID 1.3.6.1.5.5.7.3.1)● Subject Name must exactly match the RDG’s external FQDN,

must also match internal FQDN if used internally.● Must be installed to the local computer’s Personal Store and

not the current user’s Personal Store

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SSL Certificates

• Server certificate attributes● Must be a computer certificate● Extended key usage must be for Server Authentication

(OID 1.3.6.1.5.5.7.3.1)● Subject Name must exactly match the RDG’s external FQDN,

must also match internal FQDN if used internally.● Must be installed to the local computer’s Personal Store and

not the current user’s Personal Store

• Although it is possible to create free certificates through 2008 Certificate Services, save yourself headache and heartache and BUY ONE.

● $20/year at GoDaddy, automatically trusted, and useful for multiple steps in this process

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SSL Certificates

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RD CAPs and RAPs

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RD CAP RD RAP

The “Who” The “What”

Concerned about RDG Performance?

• Don’t be.

• Microsoft asserts that a single RDG server can support up to 1200 concurrent connections.

● Dual-processor server with 4GB of RAM.● Virtualizing RDG is suggested.● Important Note: Windows Server Standard Edition has a hard

limit of 256 concurrent connections.● Enterprise and Datacenter Edition have no connection limits.

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DEMO:RDG Settings & Configuration

Exposing the RemoteApp

• Once the RDG is installed, this creates the pathway by which RemoteApps can flow.

• The next step is tocreate the RemoteApp.

● Install an application.● Expose the application

using RemoteApp Manager● Enable RDG settings within

the RemoteApp● Distribute the RemoteApp

through one or moremechanisms

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Special RDG Settings

• Two settings on this screen need special attention:

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Enables single sign-on between RDG and RDSH

Enables direct RDSH access for LAN clients

Too Many Error Messages!

• At this point, your clients can invoke the RDP file to connect either locally or via the Internet.

• However, for reasons of scripting security, Microsoft requires an authentication at connection.

• This confuses users.• Creates pain for

we admins.

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Eliminate Error Messages!

• Eliminate one of the two error messages by digitally signing your RDP file.

• Possible to use same servercertificate as installedto RDG.

• Install certificate to RDSH’slocal computer PersonalStore.

• You’ll know if you screwedthis part up.

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Error Messages to Questions

• Signing the file creates the necessary authentication between client and server.

● Prevents RDP file from being tampered with.● RDP files cannot be modified in any way, or it will break the

certificate signage.

• However, it doesn’t entirely eliminate the error message.● Instead, the user sees: “Do you trust the publisher of this

RemoteApp program?”● User can click Yes, also can click “Don’t ask me again”.

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Securely Extending RDS to the InternetHow to Internet-Enable your Applications

Greg Shields, MVPSenior Partner and Principal Technologist

www.ConcentratedTech.com