Q:

Change allowed mail size quota

The email server on my ubuntu machine can only receive mails up to 10 megabytes in size.
I would like to change that value, but I'm so blind I can't figure out where to change it.
Could not be delivered because of

Server refused mail at MAIL FROM - 552 5.3.4 Message size exceeds fixed limit

A:

If you use Postfix

add "message_size_limit = 102400000" in "/etc/postfix/main.cf"
reload postfix: sudo postfix reload
check message_size_limit

Example(100Mb):
$ sudo postconf message_size_limit
message_size_limit = 102400000

This is documented on the Postfix site:

message_size_limit (default: 10240000)
The maximal size in bytes of a message, including envelope information.
Note: be careful when making changes. Excessively small values will result in the loss of non-delivery notifications, when a bounce message size exceeds the local or remote MTA's message size limit.

