Is there a feasable way to detect and stop spam being sent from your servers by a ligitimate-appearing client?

I had thought to limit accounts to a certain number of emails per day, after which number the account is flagged for review, but I have heard that there are CGI and ASP.NET scripts that use a direct send system (such as AspNetEmail). Is there a safe way to block this type of activity on an account by account level?

Would not want to block legitimate companies (that I have verified) from sending as many emails as they want, but I do not want a unverified customer sending a few hundred thousand emails when my back is turned.

Any input appreciated!


Dave

I had this same problem with my free webhosting users and had to develop a system to handle it. With alittle time and research you should be able to limit based on users using alittle patching to whatever you're looking to limit. :)

It would be a good idea to install spam assassin.
You can have it for individual accounts or have it server wide.

Regards
Amar