abused webmail

["columbo" <postfix@xxxxxxxxxx>]

Hello,

 

I would like to find some solution against spammers, who are abusing our webmail, based on Iplanet Messagging server. (or how do the SUN  call it now:)

They (spammers) probably use some simple POSTing script through which they cram thousands of messages.

There are postfix MTA servers in the frontend network and messages from backended webmail are forwarded to them. Presently we are not able to stop

them right on the backend, we need to cut them down on the outgoing postfixes.  So what we need is to limit number of messages in for example

five minutes, coming from one concrete address (webmail backend) and from one concrete user (From:webmailuser@xxxxxxx) together. 

Any idea how to handle this?

 

Thank you for any help.

Mesijeur Grygar