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Knowledgebase: Mailing Lists/ezmlm
Bulk Mailing (ezmlm, VB, etc...) Message Size Limits
Posted on 12 September 2005 10:14 PM

Is there a max size limit for messages sent to mailing lists?


There is a maximum limit of 1,400,000 bytes (approximately 1.3 MB) for each mailing list message sent from the FutureQuest servers. This includes messages sent via ezmlm, vBulletin, and other software used to send bulk messages.

If you wish, you can reduce the maximum message size limit for a particular ezmlm-idx list (note: legacy ezmlm lists do not have this ability). To do so, you will need to modify the msgsize file for that list. This file can be found at:
(where items in italics are replaced with your specific account information)

As standard, this file contains:

To adjust the maximum message allowance, simply change the 1400000 value to a lower value. (Note: Adjusting the size higher will not result in the ability to send messages larger than 1400000 bytes.) The "2" is the minimum accepted size and can be adjusted as well, if desired. Both of these numbers are in bytes.

For example, the following setting would change the maximum accepted message size to 600,000 bytes (while retaining the 2 byte minimum):

Note that binary files attached to an email must be encoded before being sent through the mail server. This means the actual email, after encoding, can be 1.5 times the original size (or more) depending on encoding.

It is recommended to upload larger files to a web-accessible location and provide the link in the email instead.

Other limitations for mailing lists can be found at: