Max message size

Rick Chadderdon mailscanner at
Wed Aug 9 16:23:11 IST 2006

Doron Shmaryahu wrote:
> Hi,
> I am using the max message size for individual users and it works great.
> I just want to know how I sort of whitelist all local users sending mail
> to each other from being limited. The is the sort of config I am looking
> for:
> user at localdomain to user2 at localdomain no message size limit
> Then apply all the other limits ie external mail limited to 500k.
> Thanks in advance
> Doron
If you're using Postfix, you'll also need to set a higher limit in your 

Keep in mind that "unlimited" (or very high) message size can cause a
lot of problems if you have users with no common sense or users who
don't have at least a basic understanding of how email works.  If you
have a large number of users, you will have at least a few of each type.

I made such an allowance once for one of my domains.  Issues that showed
up on the first day:

1.  Local users sending *huge* attachments to each other - on the order
of several hundred megabytes.

2.  Users sending very large attachments to people on the same domain
who checked their email from home or elsewhere.  The receiving user
would invariably think their email client had hung, close it and try
again.  This would cause a number of problems, depending on what the
client was.

3.  Users sending mail from home or elsewhere to other users on the same
domain.  This was worse than the above, because the upsteam bandwidth
for even most broadband users is very low.  It doesn't take a very large
file for someone with, say, 256Kb of upstream bandwidth to make their
mail client appear to have hung while sending.  I had one user with
about fifteen connections to the mail server waiting to time out because
he'd kept killing and restarting his mail client.

I ended up dropping the limit back down and setting up a personalized
web repository for users who want to exchange large files.  Email is
not, and never has been, the way to transfer large files. 


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