[This is pre-release documentation and subject to change in future releases. This topic's current status is: Milestone-Ready]

Topic Last Modified: 2010-07-16

You must configure Domain Name System (DNS) records for internal and external edge interfaces, including both Edge Server and reverse proxy interfaces.

Note:
By default, DNS uses a round robin algorithm to rotate the order of resource record data returned in query answers where multiple resource records of the same type exist for a queried DNS domain name. Communications Server 2010 DNS load balancing depends on this mechanism. Make sure this setting has not been disabled, and if using a DNS server that is not running a Windows operating system, verify that round-robin resource record ordering is enabled.

Use the following procedures to create and verify each DNS SRV record and DNS A record required for external user access. For details about each record required to support External User Access, see Determining DNS Requirements.

To create a DNS SRV record

  1. On the appropriate DNS Server, click Start, click Control Panel, click Administrative Tools, and then click DNS.

    Note:
    The external DNS for external DNS lookups by remote users and federated partners, the DMZ DNS for records required by the Edge Servers themselves, or the internal DNS for lookups by internal clients and Communications Server 2010 servers.

  2. In the console tree for your SIP domain, expand Forward Lookup Zones, and then right-click the domain in which Communications Server 2010 is installed.

  3. Click Other New Records.

  4. In Select a resource record type, type Service Location (SRV), and then click Create Record.

  5. Provide all required information for the DNS SRV record.

To create a DNS A record

  1. On the DNS Server, click Start, click Control Panel, click Administrative Tools, and then click DNS.

  2. In the console tree for your SIP domain, expand Forward Lookup Zones, and then right-click the domain in which Communications Server 2010 is installed.

  3. Click New Host (A).

  4. Provide all required information for the DNS SRV record.

To verify a DNS record

  1. Log on to a client computer in the domain.

  2. Click Start, and then click Run.

  3. At the command prompt, type nslookup <FQDN edge interface>, and then press ENTER.

  4. Verify that you receive a reply that resolves to the appropriate IP address for the FQDN.