Hi, it seems the resolver was rewritten (probably in postfix 3.1.x), but it seems it now uses res_query instead of the res_search which results in RES_DEFNAMES and RES_DNSRCH not supported with smtp_host_lookup=dns, example: # postconf -e "relayhost = [smtp]" # postconf -e smtp_host_lookup=dns # postconf -e "smtp_dns_resolver_options = res_defnames, res_dnsrch"
With postfix-3.0.7 (and also postfix 2, e.g. postfix-2.11.3) if there is SMTP relay smtp.example.com then sending mail through such relay by e.g. the following command: # echo hi | sendmail u...@example2.com works as expected (verbose logging enabled): postfix/smtp[9569]: smtp_parse_destination: [smtp] smtp postfix/smtp[9569]: connecting to smtp port 25 postfix/smtp[9569]: smtp_addr_one: host smtp postfix/smtp[9569]: lookup smtp type A flags 640 postfix/smtp[9569]: dns_query: smtp (A): OK postfix/smtp[9569]: dns_get_answer: type A for smtp.example.com. Flags 640 (0x280) are RES_DEFNAMES|RES_DNSRCH, /usr/include/resolv.h: #define RES_DEFNAMES 0x00000080 /* use default domain name */ #define RES_DNSRCH 0x00000200 /* search up local domain tree */ But the same configuration now doesn't work with postfix 3.1.x+, e.g. postfix-3.4.8: postfix/smtp[3285]: smtp_parse_destination: [smtp] smtp postfix/smtp[3285]: connecting to smtp port 25 postfix/smtp[3285]: smtp_addr_one: host smtp postfix/smtp[3285]: lookup smtp type A flags RES_DEFNAMES|RES_DNSRCH postfix/smtp[3285]: dns_query: smtp (A): Host not found Is this intended? I wasn't able to find any related incompatibility notice in the documentation thanks & regards Jaroslav
