Article ID: 251509 - View products that this article applies to.
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When you use a domain name to restrict access to an IMAP or POP3 virtual server, you need a pointer (PTR) record for that domain in Domain Name System (DNS). Otherwise, the restriction does not work because Exchange 2000 cannot perform a DNS reverse lookup successfully to obtain the fully qualified domain name (FQDN).
The PTR record is a resource record that is used in a reverse lookup zone that is created within the in-addr.arpa domain to designate a reverse mapping of a host IP address to a host DNS domain name.
To add a pointer (PTR) resource record to a reverse zone: