Postfix sometimes deliver emails and sometimes not

Question

Im using postfix 2.3.3 on RHE5, since some weeks ago, we had an email delivering issue, being specific with external relay (gmail, hotmail, yahoo).

I made some exercises: send one email to an internal email address with CC external address.

We receive with our client (Thunderbird) the internal email without problem, but we don't receive the external (I viewed the spam mail and nothing) . I check the postfix log and it's says that everything is okay.

Aug 29 16:55:43 mail postfix/smtpd[2019]: A1DA879E809: client=unknown[192.168.26.6]
Aug 29 16:55:44 mail postfix/cleanup[2022]: A1DA879E809: message-id=<57C4BB64.7030807@internaldomain>
Aug 29 16:55:47 mail postfix/qmgr[1771]: A1DA879E809: from=<account1@internaldomain>, size=114602, nrcpt=2 (queue active)
Aug 29 16:55:47 mail postfix/smtpd[2019]: disconnect from unknown[192.168.26.6]
Aug 29 16:55:47 mail postfix/local[2032]: A1DA879E809: to=<internaltest@internaldomain>, relay=local, delay=4, delays=4/0.04/0/0.01, dsn=2.0.0, **status=sent** (delivered to maildir)
Aug 29 16:55:53 mail postfix/smtp[2031]: A1DA879E809: to=<address@gmail.com>, relay=gmail-smtp-in.l.google.com[108.177.11.27]:25, delay=10, delays=4/0.03/2.8/3.3, dsn=2.0.0, **status=sent** (250 Requested mail action okay, completed.)
Aug 29 16:55:53 mail postfix/qmgr[1771]: A1DA879E809: removed

I check our queue but nothing seems wrong

qshape deferred
                                         T  5 10 20 40 80 160 320 640 1280 1280+
                                  TOTAL  7  0  0  0  1  0   0   0   0    0     6
                              oj.gob.gt  4  0  0  0  0  0   0   0   0    0     4
                             gmaiil.com  1  0  0  0  0  0   0   0   0    0     1
                          cocisa.com.gt  1  0  0  0  1  0   0   0   0    0     0
                       energuate.com.gt  1  0  0  0  0  0   0   0   0    0     1

What could be happening??

Our basic postfix configuration is this:

alias_maps = hash:/etc/aliases
bounce_queue_lifetime = 1d
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
debug_peer_level = 2
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
mailbox_size_limit = 102400000
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
maximal_queue_lifetime = 1d
message_size_limit = 20971520
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mydomain = domain
myhostname = mail.domain
mynetworks = 172.16.0.0/23,192.168.0.0/18,127.0.0.0/8
mynetworks_style = subnet
myorigin = $mydomain
newaliases_path = /usr/bin/newaliases.postfix
readme_directory = /usr/share/doc/postfix-2.3.3/README_FILES
relay_domains = $mydestination
sample_directory = /usr/share/doc/postfix-2.3.3/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtpd_banner = $myhostname ESMTP Mail Institucional
smtpd_helo_required = yes
smtpd_recipient_restrictions = permit_mynetworks, permit_inet_interfaces, permit_sasl_authenticated, reject_unauth_destination
smtpd_sasl_security_options = noanonymous
unknown_local_recipient_reject_code = 550

score 1 · Answer 1 · edited Mar 17 '17 at 10:13

Many mail servers silently ignore Spam and messages they believe to be Spam. Check the Spam folder to see if you made it that far.

See the What are the canonical answers we've discovered over the years? and check the email section. I've written several blog posts on email including one on Running an Email Server. Try sending an email to one of the listed test addresses.

If you correctly implement SPF, DKIM and DMARC with a reporting address, Gmail and Yahoo may send you reports indicating why your mail isn't getting delivered.

Postfix sometimes deliver emails and sometimes not

1 Answers1