Re: Comcast problems again

Speaking as someone who has a test lab setup in my home office I suggest
you simplify your network to have the "prod" net directly off the main
router.  You can use subinterfaces on the cisco to support this if you
don't have enough ports.  The problems you are having may be (and I
suspect are) from your "internal" network (firewall rules, routing
issues, etc).  EVERYTIME you have a problem you will need to change your
network config to rule out problems from your internal config.

What I suggest is something like this:

internet	----	primary router 	-----	prod network
				\------	-----	test network

Excuse the simple ascii art.  Hopefully it makes things clear and helps
out.

As for some of the other questions I'm not really sure you have a total
grasp on how things work.  It is hard to detect if the source of a web
connection has undergone NAT and disallow or throttle those connections
(some protocols put the source IP inside the packet but HTTP is not
normally one of them).  I've never heard of any ISP doing that and while
comcast does MAC address lock the modem to get you to buy "additional
computers" simply putting a firewall with NAT off the modem defeats that
rather easily.  I've never had any problems doing that (no HTTP
throttling, etc).

Comcast DOES block outgoing SMTP (tcp port 25) to anything other than
their mail servers.  You can use the submission (tcp port 587) to get
around this.  I think I suggested testing SMTP using traceroute but it
should have been using tcptraceroute since SMTP uses TCP not UDP.
Please excuse the brain fart there :)  Hope this helps,

	Trev

On Tue, 2011-05-17 at 18:49 +0000, [email protected] wrote:
> Thank you for responding.  The reason I posted is I thought I recalled
> from years ago that comcast attempted to prevent people from using
> multiple computers via NATting.  Possibly by blocking or intentionally
> slowing alternate ports used in NAPT
> 
> Gathering data is hard because I have to reconfigure the network, shut
> down computers, go downstairs to reset cable modem each time.  I have
> two computers, I used a winblows notebook and an ubuntu desktop.  My
> internal network is convoluted because I have (not used for years) a
> cisco home lab and multiple segments.  Not wanting to permanently
> allocate one of only a couple of routers with multiple ethernet ports,
> I have a small cisco (802) off of my main switch.  It is the default
> router, either routing back to some other cisco lab off of the main
> switch or to the IPCOP machine also on the main switch.  Slows my
> ethernet a little bit as traffic goes two ways over 10MB/Sec but I
> still get 3 MB/S download off of the net and has only been an issue in
> one online game system related app where I get typically 60-100
> successes out of 175 while others get 80-120 (this app creates many
> web connections in a few seconds and ends them).
> 


-- 
Trev Peterson
Advanced Reality
Email: [email protected]
Phone: +1 847 406 9018

-- 
Linux Users Of Northern Illinois (Chicago) - Technical Discussion 
http://luni.org/mailman/listinfo/luni