Tuesday, May 09, 2006

 

Block Time-Warner Pollution with one line...

Time-Warner / Roadrunner, due to gross mismanagement of their network by the system administrators, is probably one of the biggest sources of spam in the United States right now. Yes, they may be blocking some crap for their users, but they're not stopping their bone-headed users' zombied PCs from polluting the Internet proper with junk mail every second.

They use the reverse DNS mappings set up by Roadrunner, with formats like this:

cpe-24-30-166-212.socal.res.rr.com

As a result, we can assume that socal = southern california, and res= residential. If we trap the two left most hostnames, we can theoretically trap all residential IP space without having to worry about IP addresses.

Now you can fight back by denying this bastard ISP from sending mail to your sendmail server by adding a simple line:

res.rr.com 550 REJECTED Time-Warner residential IP space - your ISP POLLUTES the Internet - Get a responsible ISP - see http://YOURSPAMPAGE.COM

In the future, I'll be ferretting out more hostname conventions for residential broadband IP space that shouldn't be sending mail. This beats having to keep track of individual IP blocks.

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