Providers removing blocks on port 135?

Sat Sep 20 22:38:58 UTC 2003

--On Saturday, September 20, 2003 2:46 PM -0700 Owen DeLong
<owen at delong.com> wrote:

> I still disagree with this.  To prevent SPAM, people shouldn't run
> open relays and the open relay problem should be solved.  Breaking
> legitimate port 25 traffic is a temporary hack.

Very little spam coming off dialups and other dynamically assigned,
"residential" type connections has anything to do with open relays.
The vast majority of it is related to open proxies (which the machine
owners do not realize they are running) and machines that have been
compromised by various viruses and exploits.  These are machines that
should not be running outbound mailservers, and in most cases, the
owners neither intend nor believe that their systems are sending
mail.      Merely stating that people shouldn't run open relays
didn't stop spam four years ago and it is less likely to do so now. 

My guess is that you haven't heard of the current issue with various
servers running SMTP AUTH. These MTAs are secure by normal
mechanisms, but are being made to relay spam anyway. 

It's hard enough to get mailservers secured when they are maintained
by real sysadmins on static IPs with proper and informative PTR
records. When the IP addresses sourcing the spam are moving targets,
with "generic" PTR records, and the machines are being operated by
end users with no knowledge that their computer is even capable of
sending direct to MX mail, the situation is impossible to solve
without ISP intervention via Port filtering, etc.

> If the person running the system in question chooses to do so, yes,
> they should be able to do so.

If the person running the system in question wants to run server
class services, such as ftp, smtp, etc, then they need to get a
compatible connection to the internet. There are residential service
providers that allow static IP addressing, will provide rDNS, and
allow all the servers you care to run.  They generally cost more than
dial-ups or typical dynamic residential broadband connections.  As a
rule, you tend to get what you pay for.

--
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Margie Arbon                   Mail Abuse Prevention System, LLC
margie at mail-abuse.org          http://mail-abuse.org