The sendmail-doc package doesn't include the README found in sendmail-8.11.6/sendmail/README which is different from the sendmail-8.11.6/README After upgrading to redhat 7.1 or 7.2 sometimes maildelivery fails mysteriously. The explanation is found in sendmail/README: `When attempting to canonify a hostname, some broken name servers will return SERVFAIL (a temporary failure) on T_AAAA (IPv6) lookups. If you want to excuse this behavior, compile sendmail with -D_FFR_WORKAROUND_BROKEN_NAMESERVERS and add WorkAroundBrokenAAAA to your ResolverOptions setting. However, instead, we recommend catching the problem and reporting it to the name server administrator so we can rid the world of broken name servers. '
I have added the docu and this compiletime flag, but don't change the configuration to enable the workaround by default. Thanks, Florian La Roche