New and interesting network abuse.

Suresh Ramasubramanian ops.lists at
Tue Jan 11 07:42:40 UTC 2005

Thread that I just started yesterday about port 25 blocking and if
more ISPs werent doing this bidirectionally.

Which is what your local ISP, and other ISPs that have dialup pools, must do.


On Tue, 11 Jan 2005 01:33:00 -0600, Ejay Hire <ejay.hire at> wrote:
> My apologies if this strays off topic, but I wanted to share my recent
> experience.
> We had a collocation customer come in and request a t1 of pots lines for
> their servers, then complaints that their "security" software wasn't
> working because of our RPF checks.  As it turns out they were dialing up
> to a local isp, and sending bulk email using our bandwidth, but the
> dial-up's ip.... And receiving the TCP ack on the dial up.

More information about the NANOG mailing list