North American Network Operators Group
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Re: DNS Hijacking by Cox

  • From: Steven Haigh
  • Date: Sun Jul 22 22:16:53 2007

Quoting Sean Donelan <[email protected]>:
On Sun, 22 Jul 2007, William Allen Simpson wrote: 
Comcast still blocks port 25.  And last week, a locally well-known person
was blocked from sending outgoing port 25 email to their servers from her
home Comcast service.


MSA port 587 is only 9 years old.  I guess it takes some people longer
than others to update their practices.  Based on what I know how
comcast's abuse systems implement their port 25 restrictions, I think
it is extremely unlikely it was based on other people having her e-mail
address in their Outlook programs.

Indeed. There's just not enough info to make anything but wild guesses about this.

Some people complain ISPs refuse to take action about abuse and
compromised computers on their networks.  On the other hand, people
complain when ISPs take action about abuse and compromised computers on
their networks.  ISPs are pretty much damned if they do, and damned if
they don't.

Gotta love the techie world :)

Several ISPs have been redirecting malware using IRC to "cleaning"
servers for a couple of years trying to respond to the massive number
of bots.  On occasion they pick up C&C server which also contains some
"legitimate" uses. Trying to come up with a good cleaning message for
each protocol can be a challenge.

I'm still unsure that this is either a good idea or a bad idea... changing the DNS can only help until the bots start connecting directly to IP addresses. Then where do we go? NAT those connections to elsewhere? It's one of those lovely arms races where things just get more and more invasive.

In the short term, it's a good thing - the amount of spam I get from their network has halved - which is great - however in the long term, the writers of this crudware will find another way to do business (web? ftp?).

Yes, false positives and false negatives are always an issue. People
running sevaral famous block lists for spam and other abuse also made
mistakes on occasion.

And these people have been flamed senseless. I like to think of it as a case of the work the blocklists do is excellent and saves many a network from being overrun by spam - however there is always collateral damage from things like this. The good far outweighs the bad however.

--
Steven Haigh

Email: [email protected]
Web: http://www.crc.id.au
Phone: (03) 9017 0597 - 0404 087 474