# trying to troubleshoot weird issues

## Tonglebeak

I've got several issues as far as internet goes, but I'm going to go at this one at a time.

My first problem is: network seems to hang. Here's an example of what happened today:

Tried to load up a couple sites in firefox (facebook, etc). They were stuck on resolving the domain name. While this was going on, I started a portage rsync, which just sat there doing nothing. After I killed firefox, the rsync started to chug along just fine.

That's just one example of an issue I have. As for firefox, recompiling does no good, nor does a clean profile. Somehow, the whole network is pretty much locked until one of the programs give in. What could cause this?

lspci for ethernet : 00:0a.0 Ethernet controller: nVidia Corporation MCP77 Ethernet (rev a2)

I have an Ralink RT2500 wireless card, but that isn't in use right now according to iwconfig (and it shouldn't be in use). I'm using the built-in kernel nForce ethernet drivers on Linux h4x0r 2.6.34-gentoo-r1 #5 SMP PREEMPT Thu Jun 24 01:20:52 (64-bit)

I really don't know where to start. I can assure you that it's not my cable connection, considering I work for them repairing cable-related issues that can affect connectivity.

UPDATE: Even traceroute acts extremely weird. It'll literally sit there for about 20 seconds, before displaying another hop, but it'll say the response time was in the 10 or 20 ms range. This does not make any sense at all to me.

Second update: random behavior from netstat as well. When calling it, sometimes it will sit there about 10-15 seconds before it decides to output data.

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## Jaglover

Do you have more than one computer? 

If yes, does the other one work well? 

If not, can you boot up with some liveCD and check if problem persists?

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## Tonglebeak

Got it.

I didn't realize dhcpcd kept overwriting nameservers. First problem solved regarding facebook.com not coming up.

The second problem, which I didn't mention yet, was that particular sites were slow, and I mean slooowww. This was being caused by tcp_window_scaling. When I disabled it, everything came through much more quickly. Now my next question, what would cause tcp_window_scaling to cause certain websites to load incredibly slow?

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## Hu

 *Tonglebeak wrote:*   

> The second problem, which I didn't mention yet, was that particular sites were slow, and I mean slooowww. This was being caused by tcp_window_scaling. When I disabled it, everything came through much more quickly. Now my next question, what would cause tcp_window_scaling to cause certain websites to load incredibly slow?

 A quick search on tcp_window_scaling leads to http://lists.debian.org/debian-kernel/2007/01/msg00652.html, where it is noted that you have a broken firewall or router somewhere in your path.  Fix the infrastructure and tcp_window_scaling will work fine.

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## Tonglebeak

It would have to be on my ISP's end then (thank god I work for them). I have a direct connection to my modem, and iptables isn't running.

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## Jaglover

Your modem has probably built-in NAT router. May easily be the culprit, unless you run it in bridge mode.

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