Wietse Venema:
> The DNS query is made by the SYSTEM LIBRARY functions getnameinfo()
> and getaddrinfo(). Postfix has no control over how they work.
>
> When I test this with Postfix test programs for these functions:
>
> % ./getnameinfo 216.163.249.229
> Hostname: ms.metlifeleads.com
> Address: 216.163.249.229
>
> % ./getaddrinfo ms.metlifeleads.com
> Hostname: ms.metlifeleads.com
> Addresses: 216.163.249.229
>
> (The test programs are in the Postfix source code distribution
> under auxiliary/name-addr-test/)
>
> My non-Linux system returns one PTR result (ms.metlifeleads.com);
> the A record for this name is 216.163.249.229, and Postfix would
> be satisfied with the result.
I get a similar result on a Linux box:
$ ./getnameinfo 216.163.249.229
Hostname: ms2.smrsmetlife.com
Address: 216.163.249.229
$ ./getaddrinfo ms2.smrsmetlife.com
Hostname: ms2.smrsmetlife.com
Addresses: 216.163.249.229
Again, Postfix should work OK with this.
I'm starting to suspect that the OP may have a bad DNS implementation.
Maybe some cheap router?
> I suspect that it doesn't work this way on your system. Some Linux
> distributions require extra configuration to handle more than reply
> per query. I have forgotten what the option is.
This is the "multi on" option in /etc/host.conf; documentation
says that this affects /etc/hosts lookups, so not applicable to
DNS queries.
Wietse