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Barracuda Load Balancer ADC

How to Deploy Microsoft Exchange Server 2010 in a One-Armed Configuration

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Product Versions and Prerequisites

This article applies to the Barracuda Load Balancer ADC version 5.1 and above, with Microsoft® Exchange Server 2010.

For a full list of the prerequisites for this deployment, see Microsoft Exchange Server 2010 Deployment.

In a one-armed configuration, the ports that internal Outlook® clients use to communicate with the Exchange 2010 server using RPC must be preconfigured on both Exchange 2010 and the Barracuda Load Balancer ADC.

If you want to use a single VIP address and single FQDN for your Exchange deployment, you must use a one-armed configuration.

If your Barracuda Load Balancer ADCs are clustered, the configuration between the active and passive units is synchronized; you only need to configure the active Barracuda Load Balancer ADC.

Step 1. Configure Exchange 2010 to Use a Static Port

By default, the Exchange 2010 RPC client dynamically selects a port between 1024 and 65535. To allow for a one-armed deployment, configure Exchange to use a static port instead. For more detailed instructions on configuring Exchange 2010 with static ports and hardware Load Balancer ADCs, see the Microsoft TechNet article Load Balancing Requirements of Exchange Protocols.

On each CAS server, complete the following:

  1. Configure the static port in the registry. 
    1. Open the Registry Editor by typing regedit in the Start menu. 
    2. Navigate to HKEY_LOCL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeRpc\ParametersSystem.
    3. Add a new DWORD (32-bit) Value, and name it TCP/IP Port
      You might need to create the ParametersSystem key prior to adding the DWORD registry value. If prompted, change the Base to Decimal and set the value data to 65500 (or a port of your choice between 1024 and 65535):
      registry_editor.jpg
    4. If you have Public Folders in your deployment, repeat these steps to configure the static port in the registry of each server with the mailbox role installed that hosts a Public Folder.
  2. Change the port that clients use to connect for directory access. On each CAS server, complete the set of instructions for your Exchange version.

    1. In Windows Explorer, navigate to the Microsoft.exchange.addressbook.service.exe.config file. This file is located in the \Bin folder in the root directory of your Exchange 2010 install.
    2. Open this file in Notepad.
    3. In line 13, change the default value of 0 to 65501 (or a port of your choice within the prior specified range). The entry appears as follows:
      <add key="RpcTcpPort" value="65501" />
    1. Open the Registry Editor by typing regedit in the Start menu. 
    2. Navigate to HKEY_LOCL_MACHINE\SYSTEM\CurrentControlSet\services\MSExchangeAB\Parameters.
    3. Add a new String Value (REG_SZ type), and name it RpcTcpPort .
      You might need to create the Parameters key prior to adding the REG_SZ registry value. In this case, change the Data value to 65501 (or a port of your choice between 1024 and 65535). registry_editor2.jpg
  3. Restart the Microsoft Exchange Address Book and the Microsoft Exchange RPC Client Access  services on all the CAS and Mailbox servers that you modified.
  4. To verify that your Client Access servers are using ports 65500 and 65501, open a Windows command prompt and run:
    netstat -na
    In the output, look for TCP entries marked as LISTENING with ports 65500 and 65501. An entry is marked as LISTENING for 0.0.0.0:65500 and 0.0.0.0:65501.

Step 2. Configure CAS Services on the Barracuda Load Balancer ADC

On each active Barracuda Load Balancer ADC that handles traffic for CAS services, complete the following steps.

  1. Log into the Barracuda Load Balancer ADC, and go to the BASIC > Services page. 
  2. Add all of the services listed in Table 1. For each service, add all the real servers in the CAS array. To add a service, click Add Service and enter the values in the corresponding fields. To add a real server, click Add Server and enter the IP address and port for the server.
    Table 1. CAS Services

    NameTypeIP AddressPortSession TimeoutSSL SettingsCertificatesLoad BalancingReal Server Port
    MAPI-DCOMTCP Proxy

    VIP address for the FQDN that resolves to the CAS array
    for example, exchange.domain.local

    Note: This service is helpful in cases where there is no port restriction.

    1351200N/AN/A
    • Persistence Type: Source IP
    • Persistence Time:1200

    135

    MAPI-RPC_Client_AccessTCP Proxy

    VIP address for the FQDN that resolves to the CAS array
    for example, exchange.domain.local

    Note: This service is helpful in cases where there is no port restriction.

    655001200N/AN/A
    • Persistence Type: Source IP
    • Persistence Time:1200
    65500

    MAPI-Global_Address_Book

    TCP Proxy

    VIP address for the FQDN that resolves to the CAS array
    for example, exchange.domain.local

    Note: This service is helpful in cases where there is no port restriction.

    655011200N/AN/A
    • Persistence Type: Source IP
    • Persistence Time:1200
    65501
    Exchange_Web_ServicesInstant SSL

    VIP address for the FQDN that clients use to access the CAS array
    for example, exchange.domain.local

    Note:

    • This service is useful when there are port restrictions, and traffic is allowed only for port 443.
    • To create an HTTP redirect service automatically, you must create an Instant SSL service.
      Changing an HTTPS service to an Instant SSL service does not automatically create a HTTP redirect service.
      For more information about Instant SSL, see Instant SSL Service.

    Port: 443

    HTTP Service Port: 80

    1200
    • Secure Site Domain – Enter the domain name of your Exchange server. If the internal and external domain are different, you can use wildcard characters. For example: *.barracuda.com

    • If your Barracuda Load Balancer ADC is running version 5.1.1 and above, set the Rewrite Support option to On. For versions below 5.1.1, this option is named Instant SSL.

    Select the certificate that you uploaded when preparing your environment for SSL offloading. See Step 2 in the "Deploying Exchange Services on the Barracuda Load Balancer ADC" section of Microsoft Exchange Server 2010 Deployment.
    • Persistence Type: HTTP Header
    • Persistence Time:1200 
    • Header Name: Authorization
    80
  3. If you have the Barracuda Load Balancer ADC 640 and above, you can enable Application Security for Exchange_Web_Services.
    1. For Application Security, select Enable.
    2. For Security Mode, select the Passive mode. It is recommended that you run the service in Passive mode before going active. 
    3. From the Security Policy list, select owa2010. This policy is predefined for all Exchange applications. If you want to edit the policy settings, go to the SECURITY > Security Policies page

    4. You need to modify the default owa2010 policy. Go to the SECURITY > Security Policies page and select the owa2010 security policy. In the Cookie Security section, set Tamper Proof Mode to None.

      If you want to use Integrated Windows Authentication with the Exchange service, go to the Request Limits section of the security policy settings and increase the Max Header Value Length to 800.

  4. If you require any of the protocols in Table 2, add the service for the protocol.
    Table 2. Protocol Services.

    NameTypeIP AddressPortReal Server Port
    IMAP4TCP Proxy

    VIP address for the FQDN that resolves to the CAS array
    for example, exchange.domain.local

    143143
    IMAP4 SSLTCP Proxy

    VIP address for FQDN that resolves to CAS array
    for example, exchange.domain.local

    993993
    POP3TCP Proxy

    VIP address for FQDN that resolves to CAS array
    for example, exchange.domain.local

    110110
    POP3_SSLTCP Proxy

    VIP address for FQDN that resolves to CAS array
    for example, exchange.domain.local

    996996

Step 3. Configure the Real Servers for Exchange_Web_Services

For Exchange_Web_Services only, configure health checks for all of its real servers :

  1. On the BASIC > Services page, click Edit next to the entry of the real server.
  2. Scroll to the Server Monitor section, and enter the values in the corresponding fields.

    Testing MethodPortTest TargetTest MatchAdditional HeadersStatus CodeTest Delay
    Simple HTTPS443/owa/auth/logon.aspx (unless you modified the default path of logon.aspx)Microsoft CorporationUser-Agent: Barracuda Load Balancer ADC Server Monitor20030
  3. Click Save Changes.

Step 4. Create Content Rules for Exchange_Web_Services

Create content rules for Exchange_Web_Services to maintain persistence for Outlook Web Access, Exchange Control Panel and Exchange Web Services.

  1. On the BASIC > Services page, add the rules in Table 3. To add a rule, click Add Content Rule under Exchange_Web_Services in the left pane. Then enter the values in the corresponding fields.

    Table 3. Content Rules for Exchange_Web_Services

    NameHost MatchURL MatchPersistence MethodPersistence TimeCookie Name
    OWA*/owa/*Cookie Insert1200sessionid
    ECP*/ecp/*Cookie Insert1200sessionid
    EWS*/ews/*Cookie Insert1200sessionid
  2. If you are using Outlook Anywhere (HTTPS only, not RPC over HTTPS), you must also add the following content rule for the Offline Address Book.

    NameHost MatchURL MatchPersistence MethodPersistence TimeCookie Name
    OAB*/oab/*Cookie Insert1200sessionid
  3. For each of the Content Rules you have configured, you need to add the appropriate Microsoft Exchange server(s). Select each Content Rule and click Add Server and specify your Microsoft Exchange server(s).

  4. If SNI is enforced on the Microsoft Exchange server(s), then you need to configure the following options. Go to the BASIC > Services page and click Edit for each affected server.

    1. Change the port on the server to 443.

    2. Navigate to the SSL section and set Server uses SSL to On.

    3. Expand Settings and set Enable SNI to Yes.

Step 5. Configure Hub Transport Services on the Barracuda Load Balancer ADC

On each active Barracuda Load Balancer ADC that handles traffic for Hub Transport Services, configure Hub Transport Services for Exchange 2010.

If your real servers are consolidated with both the CAS and HUB roles installed, add each server for each service that you create. If the Hub Transport role is installed on separate servers (other than those with the CAS role), add only the servers with the Hub role installed. The created services load balance the SMTP traffic to the Hub transport servers for incoming client SMTP connections.

Never configure the Exchange Hub Transport to communicate with other internal Microsoft Exchange Hub Servers via the Barracuda Load Balancer ADC. Only use the service on the Barracuda Load Balancer ADC for client connections or inbound connections from other organizations.

On the BASIC > Services page, add the following SMTP service and, optionally, the SMTP-SSL service. To add a service, click Add Service and enter the values in the corresponding fields. To add a real server, click Add Server and enter the IP address and port for the server.

NameTypeIP AddressPortReal Server Port
SMTPTCP Proxy

VIP address for the FQDN that resolves to the CAS array
for example, exchange.domain.local

25

25

 

(Optional) SMTP-SSLTCP ProxyVIP address for the FQDN that resolves to the CAS array
for example, exchange.domain.local
587587

Step 6. Configure an HTTP Request Rewrite Rule

To simplify access to the Outlook Web Access site for your users, configure a rewrite rule to add /owa to the end of the URL.

  1. Go to the TRAFFIC > Web Translations page.
  2. From the Service list, select Exchange_Web_Services.
  3. In the HTTP Request Rewrite section, add the following rule. Click Add Rule and enter the values in the corresponding fields.

    Rule NameSequence number  ActionOld ValueRewrite ValueRewrite Condition
    OWA3Redirect URL //owa*
  4. Click Save.

Next Steps

Your installation is complete. You can now test your setup and configure access control to your applications. For instructions, see:

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