Unable to send email alerts

kiekar

Hello,
I have two ubuntu servers where one has mailcow installed and the other server is used for hosting a web site.
I have setup on both machines for unattended security updates and configured to send email each time an update was done.

For test purposes, I installed postfix and mailx on the server hosting the website and configured it to use googles smtp as a relayhost configured in the postfix main.cf file server which works however I would like to use my mailcow server to send out the alerts instead.

If I use mail.mydomain.com for relayhost entry it doesn’t work. I added my trusted network but still did not work.

How would I go about using my mailcow as an relayhost to get email alerts on both machines. Your help would be much appreciated.

Thanks

aaronsmith

Sounds like you’re trying to setup a trusted network for an unauthenticated relay of messages from your web server?

When you say “it doesn’t work”, what do you mean? Are there errors / does the message get marked as spam? Can you share details on your trusted network configuration?

Did you check the postfix container logs whenever the web server tries to send an email?

Other thing to make sure is that the IP/interface being used by the web server to connect to mailcow is the same one that you’re configuring for your trusted network.

Another thing to check is firewalls if postfix isn’t even seeing a connection from your web server.

http://www.postfix.org/postconf.5.html#mynetworks

kiekar

When you say “it doesn’t work”, what do you mean? Are there errors / does the message get marked as spam?

I receive no error message. below is what is shown from the mail.log file on my webserver after sending a test message
which never arrives in my mailbox.

Oct 4 19:09:53 serv1 postfix/pickup[72931]: B7BECFE03E6: uid=0 from=<root>
Oct 4 19:09:53 serv1 postfix/cleanup[76050]: B7BECFE03E6: message-id=20221004230953.B7BECFE03E6@mydomain.com
Oct 4 19:09:53 serv1 postfix/qmgr[72932]: B7BECFE03E6: from=root@mydomain.com, size=429, nrcpt=1 (queue active)
Oct 4 19:09:53 serv1 postfix/local[76052]: B7BECFE03E6: to=karl@mydomain.com, relay=local, delay=0.13, delays=0.09/0.01/0/0.02, dsn=2.0.0, status=sent (delivered to mailbox)
Oct 4 19:09:53 serv1 postfix/qmgr[72932]: B7BECFE03E6: removed

trusted network configuration

myhostname = mail.mydomain.com
mynetworks = 127.0.0.0/8 172.22.1.0/24 172.16.0.0/24 192.168.10.0/24 10.10.0.0/24

postfix logs from mailcow.
10/04/2022, 07:08:30 PM info disconnect from unknown[172.16.0.11] helo=1 mail=1 rcpt=1 data=1 commands=4
10/04/2022, 07:08:30 PM info timeout after END-OF-MESSAGE from unknown[172.16.0.11]

I’m able to send and receive a test email using telnet on port 25 from web server to mailcow server.

both my webserver and mailcow server are on the same trusted network 172.16.0.0/24

ufw is not enabled on mailcow server.
ufw is enabled on webserver with port 25 and 587 open

Postfix main.cf file on webserver

myhostname = mydomain.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname, mydomain.com, serv1, localhost.localdomain, localhost
relayhost = [mail.mydomain.com]:587
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_security_level = may
header_size_limit = 4096000

sasl_passwd file

[mail.mydomain.com]:587 karl@mydomain.com:mypassword

aaronsmith

Given you said you can perform a test email via port 25 suggests your base configuration is correct.

But this message is of interest to me:
“timeout after END-OF-MESSAGE from unknown[172.16.0.11]”

Also notice “commands=4”, I believe there should generally be 7 commands completed, but I could be wrong there.

Checking my mailcow, I see no such timeout messages and 7 commands completed by time of disconnect. Seems like the delivery is not completing from your web server’s postfix for some reason?

Maybe check the rspamd logs on mailcow? Perhaps its treating the message as spam and rejecting it silently?

kiekar

I was able to send a test mail from my webserver to mailcow server by commenting out mydestination in the postfix main.cf file

kiekar

How would I now configure mailcow to have unattended security emails sent locally on the mailcow machine. Postfix main.cf file is not found in /etc/postfix location

aaronsmith

The main.cf file for your dockerized postfix in mailcow is found in data/conf/postfix. The contain’s directories are mapped to these files on the local system.

kiekar

Got it working by install postfix and following this instruction (https://docs.mailcow.email/post_installation/firststeps-local_mta/)