max size PER email per address

[flamewalker]

Is there an easy way to set the maximum size of an incoming email, per email address?

My situation is this: We are a local ISP, and we have customers on dialup (I know... sad, but DSL/Cable isn't everywhere!). When people send these dialup users large emails (jokes, videos, etc), we have to log in and manually remove the offending emails so they can get the rest.

I know I can set a whole mailbox size limit, which might be a somewhat workable solution, but I would also like to bounce messages, say, above 1mb, for our customers using dialup.

Any ideas?

TIA.

 

[nobaloney]

Short answer: it can be done. How easily depends if you want one size limit for all mailboxes or if you want to have the maximum limits on a per-user or per virtual email address basis.

First note that you should never bounce messages for any reason. The way spammers work, if you bounce messages you're going to send them back to people who didn't send them; you'll be guilty of collateral spam. That's something an ISP should try to avoid.

And of course you shouldn't throw it away after accepting it either; people should know if their email is delivered.

That leaves rejecting the email on receipt, so the sending server knows what to tell the original sender.

You don't know the size of the email until after you've accepted the data. While it is possible to reject email in the check_message ACL (it's at EDIT#46 in my latest SpamBlocker exim.conf file [nobaloney.net]) and in fact that's how we reject viruses, it requires a bit of work.

One of the lines in that ACL shows you how to check for message size; anoher shows you how to reject; just add a stanza to that ACL.

The problem is that if you want to use different limits for different users you'll need to create your own table and lookup system.

Or hire someone to do it for you.

For what it's worth, we got out of the dial-up access business when the Telco/Cable duopoly took hold; you can't easily compete when you buy your competitor's pipe for last-mile delivery, and our area is sufficiently urban that DSL and CABLE are both ubiquitous. My local cable company gives me 20MB down, about 2MB up, for about $60/month. Don't even want to try to compete. So we sold of our customers and concentrating on webhosting, where most of the ISPs just don't have a clue.

And soon after we shut down our ISP services, our competitor (the local newspaper) sold out to Earthlink. Either they saw the light as well, or they were just staying to compete with us.

Jeff