Hi list We have an "issue" with postfix where we do not really understand why it could happen. As our configuration should tell postfix to behave otherwise.
in main.cf smtp_address_preference = ipv4 inet_protocols=all which should ensure postfix client prefers ipv4 over ipv6 But now we have a mail where we can see that postfix client did AAAA lookup. Although the is a valid A record > Dec 29 07:43:34 10.1.0.201 postfix/smtp[38913]: 4JP20t6xYdz3VMH: to=<REDACTED>, relay=none, delay=7.5, delays=1.2/0/6.3/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=REDACTED.mail.protection.outlook.com type=AAAA: Host not found, try again) DNS response for AAAA is an empty NOERROR According to log it took postfix over 2min to "fallback" to ipv4 > Dec 29 07:46:04 10.1.0.201 postfix/smtp[60301]: 4JP20t6xYdz3VMH: to=<REDACTED>, relay=REDACTED.mail.protection.outlook.com[104.47.5.36]:25, delay=158, delays=154/0.07/2.3/1.4, dsn=2.6.0, status=sent (250 2.6.0 <gvap278mb045483a63f074170ecb896bddf...@gvap278mb0454.chep278.prod.outlook.com > [InternalId=8980776622596, Hostname=GVAP278MB0794.CHEP278.PROD.OUTLOOK.COM] 194304 bytes in 0.307, 617.607 KB/sec Queued mail for delivery) And that's what we do not understand. Why it took postfix that long to fallback to ipv4 which should be the preferred one anyway according to our config? Cheers and have a good one tobi
