Howdy folks! I recently encountered a situation where some open SMTP relay checking was in order for a large enterprise. I returned to this thing I wrote almost 3 years ago, and really beefed it up. I can say that I covered 16 class b subnets in about 40 minutes, and that was before adding some timeout handling to the script. It was received well enough, that it's being deployed as a cron job for regular dedicated relay scanning.
I think it's useful, especially for a large enterprise, so I thought I'd share
http://stormthe.net/tools/php2relay.txtInformation about the upgrades, more background and such are in the comments of the script. I'm happy to take feedback...
-rance
Tutorials : Need guidance 
