I've been having an issue to send mails, mostly to domains using Outlook.com as mailserver.
For example:
Jul 5 15:38:20 vm-dns-mail postfix/smtp[29249]: B6A3A20113E: to=<[email protected]>, relay=none, delay=189023, delays=189019/0.05/4/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=grassvalley-com.mail.eo.outlook.com type=AAAA: Host not found, try again)
But it has a correct MX record:
vm-dns-mail ~/bin # dig mx grassvalley.com
[...]
;; ANSWER SECTION:
grassvalley.com. 7362 IN MX 5 grassvalley-com.mail.eo.outlook.com.
And I can telnet to it:
vm-dns-mail ~/bin # telnet grassvalley-com.mail.eo.outlook.com 25
EHLO
Trying 207.46.163.30...
Connected to grassvalley-com.mail.eo.outlook.com.
Escape character is '^]'.
220 CO9EHSMHS019.bigfish.com Microsoft ESMTP MAIL Service ready at Fri, 5 Jul 2013 19:45:12 +0000
250-CO9EHSMHS019.bigfish.com Hello [85.12.6.130]
250-SIZE 157286400
250-PIPELINING
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-AUTH
250-8BITMIME
250-BINARYMIME
250 CHUNKING
I thought it was an IPV6 issue, as this VM is unable to connect to IPV6. So I added this line to main.cf:
inet_protocols = ipv4
But it merely changed the issue to this:
Jul 5 21:41:38 vm-dns-mail postfix/smtp[30661]: C1102201234: to=<[email protected]>, relay=none, delay=2, delays=0.01/0/2/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=cjp-be.mail.eo.outlook.com type=A: Host not found, try again)
What could cause this, rather annoying, problem?