I'm attaching a simple test program which can be used to see the problem, which appears to still be present in 12.10:
$ host ptr-mismatch.kerberos.org ptr-mismatch.kerberos.org is an alias for www.kerberos.org. www.kerberos.org has address 18.9.62.44 $ host www.kerberos.org www.kerberos.org has address 18.9.62.44 $ host 18.9.62.44 44.62.9.18.in-addr.arpa domain name pointer KERBEROS-ORG.MIT.EDU. $ cc canonname.c $ ./a.out www.kerberos.org www.kerberos.org $ ./a.out -a www.kerberos.org KERBEROS-ORG.MIT.EDU $ ./a.out ptr-mismatch.kerberos.org www.kerberos.org $ ./a.out -a ptr-mismatch.kerberos.org KERBEROS-ORG.MIT.EDU Without AI_ADDRCONFIG, getaddrinfo does the right thing: it follows a CNAME record (like ptr-mismatch.kerberos.org) and returns the name of the A record. With AI_ADDRCONFIG, getaddrinfo performs a PTR lookup. This also happens if ai_family is set in the hint (e.g. to AF_INET); that path isn't exercised in the test program. ** Attachment added: "Test program for AI_CANONNAME" https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/1057526/+attachment/3473305/+files/canonname.c -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1057526 Title: getaddrinfo returns PTR name in ai_canonname when using DNS To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/1057526/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs