Email Recipient Limit

wolfman

Any server admins out there?

I've hit a snag, where by Windows (2000 or 2003 I think) has a default recipient limit of 100. I've written an smtp service that's sits on a server that wants to send an email to say (for example) 1,000 people.

I'm aware of the limit, but how is it handled? Does the server send 10 emails to 100 users each time, opening up a new connection for each email.

Or will it just reject it, and I'll need handle it via the code in my application. I would have thought the server should handle it, otherwise each time the limit is changed, my application would need to be changed.

DrBenway

My exchange 2003 has a limit of 64000 recipients per message on the smtp virtual server properties.

However my sendmail server has a limit of 32768 bytes on the total length of all headers.

Neither of these have been changed from the defaults although the sendmail limit could have been changed by the author of the distro as i haven't recompiled it.

You need a friendly admin who doesn't mind you relaying spam through his mail servers while testing.

What error do you get back from the smtp server ?

wolfman

Found a couple of articles:
http://support.microsoft.com/default.aspx?scid=kb;en-us;303759&sd=tech

I'm just doing it via the smtp virtual server.

The default is 100 which I think the live environment is set to. It's a government project so I don't think they'll let me change it, we have very little control over the live environment. It's put in place to restrict spamming.

Fixed it anyway. Pain as in our dev and staging environments it's fine, but on live the setup is obviously slightly different. The server basically just rejects it, get a connection error. I just put a loop in my code to do 100 recipients at a time per email. Problem solved.

Cheers anyway.