In Exchange 5.5, you only configure the external DNS in the TCP/IP settings on the Exchange bridgehead server. However, in Exchange 2000, if you set only the external DNS in the TCP/IP settings on the Exchange 2000 bridgehead server, this server may not successfully deliver internal messages because it cannot find an internal DNS to query the domain controller and global catalog. All servers in the DNS search order of the Exchange 2000 bridgehead server must be able to resolve external and Internet domains.
To ensure that the Exchange 2000 bridgehead server can resolve both external and Internet domains, open the TCP/IP settings, configure the internal DNS server, and perform any of the following procedures:
- Set up the internal servers as caching servers for Internet domains.
- Set up the internal servers with forwarders to external DNS servers.
- Configure the SMTP service to use external DNS servers. To do so, click SMTP Virtual Server, click the Delivery tab, click Advanced, and then click Configure.