Providers removing blocks on port 135?

Sat Sep 20 23:24:12 UTC 2003

> I would suggest instead that you have mandatory
> sending via your relays, and allow inbound
> connections to port 25.

We're a fairly big provider on the GRIC (global roaming) network.

That means that it's not feasible for us to prevent many of our POPs' users
from contacting off-net SMTP servers.

Running an enforced SMTP service via transparent proxying wouldn't stop the
spam problem, it would just shift it and probably get the proxy system
black-listed as an open-relay's relay.

Anyway, like I said, we don't *have* a spam problem on our dialups.  By
virtue of our filters we don't have any open relays on dialup.

ADSL is a different matter and we do have occasional problems with open
relays and/or worms there.

Unfortunately the UK incumbent wholesaler(*) doesn't provide a way to filter
ADSL traffic within their ATM core.  The only way to do it is to put another
router between our network and the "BT Central" router that connects their
ATM cloud to us.  Of course that doesn't provide any inter-customer
filtering, since that traffic never reaches our network :(

Ray

(*) BT - they have a nearly complete monopoly on the local loop.