Prevent Spam on my IIS SMTP server

[centrino]

I really need some help on this.

I am running a SMTP virtual server on Windows 2003 Server IIS. I have a web application (.NET or Java) that use the service to send emails. This server is on the internet. I found other people uses my server to send spam emails out. Can anyone tell me how to prevent this?

I have the following configuration properties on my SMTP server.

- Access

Authentication : Anonymous access

Connection: only the list below 127.0.0.1

Relay: only the list below 127.0.0.1 (UNcheck allow all computer which successfully authenticate to relay..)

- Delivery

Outbound Security : Anonymous access

Here are some logs extracted: (Only the first 1 from 127.0.0.1 come from my application)

2006-01-05 14:08:26 127.0.0.1 HELO 250

2006-01-05 14:08:26 127.0.0.1 MAIL 250

2006-01-05 14:08:26 127.0.0.1 RCPT 250

2006-01-05 14:08:26 127.0.0.1 DATA 250

2006-01-05 14:08:26 127.0.0.1 QUIT 240

2006-01-05 14:08:26 64.233.163.114 - 0

2006-01-05 14:08:26 64.233.163.114 EHLO 0

2006-01-05 14:08:26 64.233.163.114 - 0

2006-01-05 14:08:26 64.233.163.114 MAIL 0

2006-01-05 14:08:27 64.233.163.114 - 0

2006-01-05 14:08:27 64.233.163.114 RCPT 0

2006-01-05 14:08:27 64.233.163.114 - 0

2006-01-05 14:08:27 64.233.163.114 DATA 0

2006-01-05 14:08:27 64.233.163.114 - 0

2006-01-05 14:08:29 64.233.163.114 - 0

2006-01-05 14:08:29 64.233.163.114 QUIT 0

2006-01-05 14:08:29 64.233.163.114 - 0

Please help!!!

[Gouki]

I recently had the same problem!

Its pretty difficult to stop them from sending Mass Email using your server, thats because they problably use a simple .PHP Script.

What you can do is find out here the .php file is, and delete it. Then, dont give access to suspicious users.

I have just noticied you have anonymous access active. Thats not a good thing to do.

This is just my opinion, its worth what its worth.