On Thu, Jan 07, 2010 at 05:58:09PM -0600, Dennis R. Abel, LLC wrote:
> Those subscribers did not have a business account and there agreement
> states the rules about the service. They had home subscriber accounts
> which do not allow web and mail servers. For a few dollars more and a
> business account those ports are open and are never blocked. 

Comcast doesn't differentiate if the ports are inbound or outbound. 

Blocking port 25 outbound happens quite alot. There have been times
when random blocks of IPs are unable to be accessed on port 80 from
Comcast customers (not happening so much any longer), as they've
fudged their filter settings.

TW blocks many more ports for their customers "protection" (ie. things
like SMB file access across the Net, as well as both directions ). 

Other providers have blocked things arbitrary like VOIP protocol ports.

These aren't people trying to run servers on their cable connection, but 
the protocol flat out is blocked from being used either direction. 
Ie. we become more involved when they are trying to get back to servers
hosted on our network in our colo. We can packet trace the packets 
leaving our network, and the customer never getting them. We know there
are no filters on anything we control, but yet it gets blocked before it
gets back to them.

-- 
Doug McIntyre                            <[log in to unmask]>
          -- ipHouse/Goldengate/Bitstream/ProNS -- 
       Network Engineer/Provisioning/Jack of all Trades