nanog mailing list archives
Re: Finding asymmetric path
From: William Herrin <herrin-nanog () dirtside com>
Date: Sat, 28 Nov 2009 17:28:01 -0500
On Sat, Nov 28, 2009 at 2:14 PM, ML <ml () kenweb org> wrote:
Brielle is correct. The customer in question is spamming networks and we are having trouble filtering them because another provider allows them to source traffic however they please.
What trouble? SMTP requires two-way traffic with a static port number that nothing else uses. If for some reason you don't want to simply terminate their account altogether, block packets outbound to your customer sourced from TCP port 25 but not from your SMTP smarthosts. Seriously though, if you can prove they're spamming (regardless of whether the packets pass through your network) save yourself some grief and just terminate the account. Regards, Bill Herrin -- William D. Herrin ................ herrin () dirtside com bill () herrin us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
Current thread:
- Re: Finding asymmetric path, (continued)
- Re: Finding asymmetric path Joe Greco (Nov 28)
- Re: Finding asymmetric path Joe Provo (Nov 28)
- Re: Finding asymmetric path Joe Greco (Nov 28)
- Re: Finding asymmetric path ML (Nov 28)
- Re: Finding asymmetric path Brielle Bruns (Nov 28)
- Re: Finding asymmetric path Duane Waddle (Nov 28)
- Re: Finding asymmetric path Arie Vayner (Nov 29)