Question : How do I fix an Exchange 2007 NDR attack and get a Spam Cleanup process?

Does someone have an article similar to
http://www.amset.info/exchange/spam-cleanup.asp
which has been posted here but only covers exchange 2003?

Our exchange 2007 server is under atttack and I am a newbie at this.
I need to block port 25, but I'm not sure how to do that on SBS2008. Or should I just stop the SMTP service?

Answer : How do I fix an Exchange 2007 NDR attack and get a Spam Cleanup process?

Sorry - but you are an open relay - I just tested it:

220 yourserver.yourdomain.com Microsoft ESMTP MAIL Service ready at Wed, 21 Jul 2010 13:45:15 -0700

May be an open relay.
0 seconds - Good on Connection time
0.281 seconds - Good on Transaction time
OK - 173.13.xxx.xxx resolves to 173-13-xxx-xxx-abcd.xyz.comcastbusiness.net
Warning - Reverse DNS does not match SMTP Banner

Please have a read of my recent blog article and close your open relay down:

http://alanhardisty.wordpress.com/2010/07/12/how-to-close-an-open-relay-in-exchange-2007-2010/