>>>>> "Cristian" == Cristian Prieto <cristian@xxxxxxxxxxxxxxx> writes: Cristian> res = res_query(name, C_IN, T_MX, answer, sizeof(answer)); This incorrectly fails if an address has an "A" record but no "MX" record. According to RFC 2821 Section 5: The lookup first attempts to locate an MX record associated with the name. If a CNAME record is found instead, the resulting name is processed as if it were the initial name. If no MX records are found, but an A RR is found, the A RR is treated as if it was associated with an implicit MX RR, with a preference of 0, pointing to that host. So, your function will say "no good" if the domain has an A record but no MX record, even though the RFC says that's OK and deliverable. Man, is there a lot of bogus knowledge and cargo culting around this subject! -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 <merlyn@xxxxxxxxxxxxxx> <URL:http://www.stonehenge.com/merlyn/> Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training! ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
