Re: Comcast problems again

On Fri, 27 May 2011 00:33:04 -0500
Trev Peterson <[email protected]> wrote:

> Carey,
> 
> Comcast is not breaking your connection due to detecting multiple PCs
> behind your NAT device.  Ask all you want about how NAT works and how
> to hide the fact you have devices behind the NAT router just do it so
> you can learn about these things.  It won't fix the issues you are
> having. Period.
> 
> If you really want to find the issue and resolve the issues
> troubleshoot it systematically.  Start by locating the bottleneck.
> 
> 1. Walk down the stack and make sure the issue is an IP one and not
> higher up (poorly performing DNS can slow things down a ton and make
> it look like it's a network throttling / congestion issue.
> 
> 2. Localize the problem.  Do a traceroute to say google then do 1000
> byte pings to each hop along the way to see where the time starts
> increasing by larger increments.  This is where it is saturated /
> being throttled. Also, test throughput to a test node outside the
> firewall on the comcast segment WHEN you are getting a slowdown.  If
> it slows down to the test node at the same time the issue is in your
> internal network.
> 
> Hopefully this helps you solve the issue,
> 
> On Thu, 2011-05-26 at 21:57 -0500, Carey Tyler Schug wrote:
> 
> > It still doesn't explain how the web side of NAT looks different 
> > compared to a single computer so Comcast can break it, and if there
> > is some way to tweak NAT so Comcast won't break it.  Like force NAT
> > to use a smaller range of translated port numbers?
> > 
> > --Carey
> 

Very good recommendations there. For number 2. I would use something
called MTR or MyTraceRoute. It works very well and shows you the
latency between you and each hop to your destination.

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