[olug] Cox and port 25

Jay Hannah jay at jays.net
Sun Jun 29 03:56:13 UTC 2003


What a strange situation... I never thought I'd be defending Cox when
they (once again) block something and piss me off. I guess I'm just a
lot angrier at spammers nowadays than ISP who try to fight them... 

Anyhoo, here's two more cents:

"Nathan Rotschafer (OLUG)" wrote:
> Now consider I run a valid business and work from home and need to send
> company email from my house what do I do?  If the email comes through Cox's
> servers some place will tag it as spam or refuse delivery based upon the fact
> that it is "forged".  Now what do I do?  In my opinion Cox just put a major
> blow to work from home business people and that is completely unacceptable.

I'm sure there are some out there somewhere, but in my experience
Internet mail servers don't ever care whether or not your From: and
Reply-To: headers match the hostname or IP that connected to them. Your
email should be accepted through Cox's SMTP gateway the same as it is
from your works. Your customers/coworkers won't even notice. 

(Other DNS problems can and do occur, but I can't think of any relevant
to this situation.)

Has anyone confirmed, with a live test, that SpamAssasin actually does
block this way? Does anyone have a single live test to any system which
does?

Tim V - DZ wrote:
> limiting, could bottleneck, and creates a single point of failure. 

There's 4 servers. I assume all 4 would accept connections from our IPs
here in Omaha:

   http://support.cox.net/custsup/email/POP_SMTP_settings.shtml

> My laptop is set up for pop/smtp on a non-cox server.  Now when I'm at
> home I'll have to change the SMTP server, and when I'm away I'll have to
> change it back...

Ouch. Ya, I can see that as an annoyance I never thought of. I can't
think of a clean way around that one...

> How much is Quest DSL?

Nick Walter wrote:
> This whole rant against Cox has made me curious; is there no DSL
> available in Omaha?

Check up on their coverage area, DSL is a little spotty. If you are
covered, you might want to check out my friend's ISP instead of Quest:

   http://www.lunargravity.net/

"William E. Kempf" wrote:
> Unfortunately, in my own situation I'm technically already in 
> violation of my contract with Cox, by running Postfix.  See 
> http://support.cox.net/custsup/policies/acceptableuse.shtml#aup_6. 

Aren't we all? -grin- I've been in a "don't ask, don't tell"
relationship with every ISP I've had for 10 years. Their AUP gives them
legal recourse to act in case I'm doing something really nasty with my
"Server". If they didn't have a clause like that they'd have no clear
legal case to shut me down, if (say), I decided to run multiple
massively multiplayer online game servers on their network.

As long as you're (we're) not hurting anything, or sucking up their
bandwidth, they don't care. We continue to live in a truce where they
have the final, legal veto, as they should to protect themselves from
abusive customers without getting sued.

(They can't *just* go by a bandwidth stipulation, because a porn/warez
downloading fiend probably doesn't have a "server", but still clogs
their network. Multiple clauses, multiple protections from unruly
customers.)

"William E. Kempf" wrote:
> Port blocking isn't going to slow spammers down.  As
> pointed out for the "solution" to our legitimate problems, the spammers
> can simply use port forwarding and other such hacks to continue.  

I don't agree. 99.99% of SMTP servers run on port 25. Blocking port 25
outbound makes 99% of Cox's Internet address space unusable for spam
propogation (intentional, hijacked, or open relays). Spammers inside
Cox's netblocks are then forced to abuse Cox's SMTP gateways which
(hopefully) they'll be aggressively monitoring for abuse (or all of this
is a mute point). Spammers only other option is to go to another ISP.

> And that assumes that all ISPs do the same port blocking, otherwise, they'll just
> use some other ISP (which Cox may think is a good thing, but doesn't mean
> a hill of beans to me, the customer).  PORT BLOCKING IS NOT A SOLUTION.

Indeed. They'll scurry off to another ISP. But with every step in the
right direction, there are fewer and fewer places for spammers to hide.
Cox just took millions of IPs out of the spammer's sandbox. What's left
for the spammers to play in is blacklisted more and more, as it should
be.

At the same time, I'm not a fan of Big Brother or sweeping actions from
monopolies. Cox chose what they chose. Customers may choose to come or
go to or from them because of it. Cox may choose to reverse their
decision. The spam struggle marches on.

Spam is bad. Eventually natural selection will work through the problem
of stomping it. People have a tendency to figure out the important stuff
eventually. Action and reaction.

> It's not even really a useful stop gap.  You want to stop spam, we either
> need laws (and some way to enforce them), or a new protocol.

Laws are good too. Just make sure to vote for congressmen and senator
who are striving to implement the right laws (OPT IN) not the very, very
wrong ones (OPT OUT).

   http://www.cauce.org/

Cheers,

j

"Forging" my mail from smtp.central.cox.net., and as far as I can tell
no one has noticed. -grin-


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