В /etc/postfix/main.cf
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_command =
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = localhost vltc.net.eu.org
inet_protocols = ipv6
при отправке сообщения на gmail:
Jul 13 00:24:02 router postfix/pickup[17457]: 2DE7B10F: uid=1003 from=<vlad>
Jul 13 00:24:02 router postfix/cleanup[17484]: 2DE7B10F: message-id=<20140712202401.GA17486@vltc.net.eu.org>
Jul 13 00:24:02 router postfix/qmgr[17458]: 2DE7B10F: from=<vlad@vltc.net.eu.org>, size=724, nrcpt=1 (queue active)
Jul 13 00:24:33 router postfix/smtp[17515]: connect to gmail-smtp-in.l.google.com[2a00:1450:4010:c04::1b]:25: Connection timed out
Jul 13 00:25:03 router postfix/smtp[17515]: connect to alt1.gmail-smtp-in.l.google.com[2607:f8b0:4003:c02::1b]:25: Connection timed out
аналогично с яндексом
Jul 13 00:30:17 router postfix/pickup[17457]: 846F715A: uid=1003 from=<vlad>
Jul 13 00:30:17 router postfix/cleanup[17730]: 846F715A: message-id=<20140712203017.GA17707@vltc.net.eu.org>
Jul 13 00:30:17 router postfix/qmgr[17458]: 846F715A: from=<vlad@vltc.net.eu.org>, size=669, nrcpt=1 (queue active)
Jul 13 00:30:47 router postfix/smtp[17732]: connect to mx.yandex.ru[2a02:6b8::89]:25: Connection timed out
Jul 13 00:30:47 router postfix/smtp[17732]: 846F715A: to=<vladislav.tcendrovskii@yandex.ru>, relay=none, delay=30, delays=0.09/0.01/30/0, dsn=4.4.1, status=deferred (connect to mx.yandex.ru[2a02:6b8::89]:25: Connection timed out)
при том, что и от яндекса и от гугла почта доходит по ipv6.