Wietse Venema wrote the following on 10/15/2013 9:55 AM:
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
Thanks for the reminder about where to locate the test programs Wietse.
I confirmed this appears to be an issue with RHEL5 (all patches applied
today). The issue is resolved in RHEL6. I am running a local instance of
BIND (bind-9.3.6-20.P1.el5_8.6) on the affected server(s).
# ./getnameinfo 216.163.249.229
getnameinfo 216.163.249.229: Name or service not known
# host 216.163.249.229
;; Truncated, retrying in TCP mode.
229.249.163.216.in-addr.arpa domain name pointer ms.metcalligo.com.
229.249.163.216.in-addr.arpa domain name pointer ms1.metlifee401k.com.
229.249.163.216.in-addr.arpa domain name pointer
ms2.fieldpayrollmetlife.com.
229.249.163.216.in-addr.arpa domain name pointer ms.nefannuity.com.
...
--Blake
