North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Stealth Blocking
Returning to operational traffic: > One thing that I think *will* help, particularly in the short term, is > port 25 blocking of dialup ports. It's my personal opinion that this > will have the greatest impact on spammers who abuse open relays. I've > watched this happen over the last few months, as various large networks > have secured their dialup ports. It's impressive. TCP rate-limiting on outbound traffic to *:25 would also be extremely effective, particularly on unclassified customer traffic, and without the heavy-handed nature of denying all dial-up traffic. Rate-limiting doesn't interfere with low-volume legitimate mail, but it really cramps spam. -- Eric A. Hall http://www.ehsco.com/ Internet Core Protocols http://www.oreilly.com/catalog/coreprot/
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