Finding asymmetric path
ops.lists at gmail.com
Sat Nov 28 21:02:31 CST 2009
Yes - term the account would be my recommendation
And if you filter port 25 traffic do it both ways
Read these old nanog threads ..
On Sun, Nov 29, 2009 at 3:58 AM, William Herrin
<herrin-nanog at dirtside.com> wrote:
> On Sat, Nov 28, 2009 at 2:14 PM, ML <ml at 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.
> Bill Herrin
> William D. Herrin ................ herrin at dirtside.com bill at herrin.us
> 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
> Falls Church, VA 22042-3004
Suresh Ramasubramanian (ops.lists at gmail.com)
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