Read the RFCs! That’s why they’re there!
Once again, I’ve been told that an IP address can only have one PTR resource record.
We got a new Internet connection in the office, and I requested 2 PTR records for an IP address on that connection to provide reverse address lookup. Can’t have email rejected for lack of a reverse IP entry. After being ignored by Support for 2 days, I sent the request to the Account Manager, who said the request was rejected because I had 2 hostnames for one IP address, and that’s not allowed.
I’ve heard this almost every time I’ve set up a new Internet connection since 1996. I can’t believe there are techs who still think this is true.
From RFC2181 (http://www.ietf.org/rfc/rfc2181.txt):
10.2. PTR records Confusion about canonical names has lead to a belief that a PTR record should have exactly one RR in its RRSet. This is incorrect, the relevant section of RFC1034 (section 3.6.2) indicates that the value of a PTR record should be a canonical name. That is, it should not be an alias. There is no implication in that section that only one PTR record is permitted for a name. No such restriction should be inferred.
Let’s go folks. Just because Jon is dead, it doesn’t mean that RFCs don’t matter anymore.