Dale Qualls wrote: >Great, thank you. > >I was wondering about the reverse DNS lookup that some mailservers do. > >If my xmailserver has a default domain of mydomain.org and a reverse DNS = >lookup pointing to mydomain.org all is well. But, if myseconddomain.org = >users send a message to a place that does reverse DNS lookups and it = >resolves back to mydomain.org, is it common for the receiving server to = >reject the message for relaying? > >
In a standard DNS configuration you would have a domain 'zone' file for each domain name and a 'reverse lookup' zone file for each block of IPs. The zone file typically has records that resolve a name to an IP address: myhost A 12.34.56.78 The reverse lookup zone file has the opposite record: 78 PTR myhost.mydomain.org The reverse lookup zone file knows what domain each IP is in. If a remote mail server does a reverse lookup and gets mydomain instead of myseconddomain, then it's configured wrong and you need to contact the ISP or whomever handles DNS for these domains. It would be good policy for the remote mail server to reject any address that fails RDNS lookup since it's most likely either spoofed or broken. Jeff - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
