How To Force Postfix To Use Only IPv4

Author: , August 12th, 2021

vi /etc/postfix/main.cf

service postfix restart

How To Fix Email Service Unavailable Delivery Issues with IPv6 on Amazon Linux

Author: , July 16th, 2021

PROBLEM: Email delivery to Google was failing with a “Service Unavailable” error:

Note that the network address for the destination is shown as IPv6! That is the root cause of the issue: 1. Sendmail is sending mail from the IPv6 address instead of the IPv4 address 2. Google rejects IPv6 senders without proper reverse […]

How To Change Your GIT Name and Email Address Globally and Per Repository

Author: , June 17th, 2021

To update your git user name and email address for all repos:

To update your git user name and email address for a specific repo:

How To Change the Destination Admin Email Address for User-Meta Pro Notifications

Author: , May 11th, 2020

How To List Running AWS Instances in all Regions Sorted by LaunchTime and Email in a Monospaced Font

Author: , July 1st, 2019

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 Force Sendmail to Process the Mail Queue

Author: , August 4th, 2016

To force sendmail to process the mail queue, execute as root: sendmail -q -v The optional -v enables verbose mode to assist with troubleshooting. To display the current contents of the mail queue, execute as root: mailq

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 […]