How To Disable Email Bounce Messages In Postfix

Author: , March 18th, 2022

How To Change The Outgoing Email Domain In MacOS

Author: , March 17th, 2022

When I sent email from my desktop Mac cron jobs, it went out with the full hostname as the domain, i.e.: root@demo.wyzaerd.com, when all I wanted was a simple root@wyzaerd.com for ease of deliverability and domain maint. Edit the mail configuration file main.cf:

Add/edit the myorigin value of $mydomain:

How To Block Email Using Subject Headers In Postfix

Author: , December 7th, 2021

I needed to block email based on the Subject header. The solution is simple: Edit main.cf as root and uncomment or add:

Next, creaate or edit /etc/postfix/header_checks as root and add the following line:

Finally, run sudo postfix reload NOTE: Do NOT add the “i” after the regular expression! It is case-insensitive by […]

How To Force Postfix To Use Only IPv4

Author: , August 12th, 2021

vi /etc/postfix/main.cf

service postfix restart

Host to Delete a Specific Email in Postfix on Linux

Author: , September 14th, 2017

root@outbound:/var/log # postqueue -p -Queue ID- –Size– —-Arrival Time—- -Sender/Recipient——- 593E2FC69D 3970 Tue Sep 12 23:15:36 MAILER-DAEMON (connect to yourDomain.com[10.10.10.10]:25: Connection timed out) yourUser@yourDomain.com — 4 Kbytes in 1 Request. root@outbound:/var/log # postsuper -d 593E2FC69D postsuper: 593E2FC69D: removed postsuper: Deleted: 1 message root@outbound:/var/log # postqueue -p Mail queue is empty

How To Send Email From the Command Line on MacOSX 10.10.5 Yosemite

Author: , January 29th, 2017

I wanted to send email from cron for various reasons, but the emails would bounce with an error 554: 554 5.1.8 : Sender address rejected: Domain not found Clearly, Postfix was using the “internal” hostname of myappledesktop.local (MacOSX has TWO hostnames! also, myappledesktop.local is not the real hostname ;-). So, I needed two things: 1. […]

How To Block an Entire TLD in Postfix

Author: , September 13th, 2016

Step 1. Execute the following two commands: postconf -e smtpd_sender_restrictions=pcre:/etc/postfix/rejected_domains postconf -e reject_unauth_destinations=pcre:/etc/postfix/rejected_domains If that doesn’t work, you may hand-edit main.cf and add/edit these lines:

Step 2. Create the regex filter file: vim /etc/postfix/rejected_domains

Step 3. Signal Postfix to reread the config: postfix reload NOTE: Do NOT use the postmap command for the […]

How To Fix a “Corrupted index cache file” Error in Dovecot

Author: , June 17th, 2016

Jun 17 00:02:45 inbound dovecot: IMAP(yourName): Corrupted index cache file /home/yourName/Maildir/dovecot.index.cache: invalid record size

As always, YMMV. Proceed with caution.

How To Modify the Maximum Allowed Attachment Size in Postfix

Author: , April 22nd, 2015

By default, Postfix restricts attachment size to about 10MB (10240000 bytes). You can check the current value by running the following command: postconf | grep message_size_limit To change the attachment size limit to say 50 MB, run a command like: postconf -e message_size_limit=52428800 You may find that the maximum mailbox size is lower than the […]

How To Use Regular Expressions (regex) To Forward Email In Postfix

Author: , April 7th, 2015

Create the file /etc/postfix/virtual-regexp. For example, forward all emails with a leading eric and ending with @thewyz.net to a Gmail account:

Edit the file /etc/postfix/main.cf. Add regexp:/etc/postfix/virtual-regexp to the virtual_alias_maps line. For example:

Generate the map .db file:

This example requires the files virtual and virtual.db to exist, even if they are […]