Web browsers "waiting for" forever on almost all sites
 

[SOLVED, see below]

Hi there,

I'm using Slack 12 (fresh install) on an Acer Aspire 1690 with an ipw2200 wifi card. I connect to the Internet through a Comtrend CT635 modem/gateway, with DHCP enabled.

Everything works fine until that point : my IP address is okay, so as the DNS.
The thing is that when I'm connecting, with any browser (lynx, links, firefox, opera), I can only access a few sites (e.g google and derivatives, mozilla.org, and a few others). For the rest of them, the browsers just hang forever "waiting for" an answer.)

I've been reading through the forums and found a similar thread (i cannot post the link since this is my first post, the thread is "internet problem:Firefox can load google, but not any others!"

So as to answser suggestions that might come first :
- DNS works fine
- Ping & Telnet work
- Iptables already flushed
- I tried changing the MTU settings of my card, to no avail
- I cannot change the MRU setting of my router (not available in the interface, if someone knows how to deal with this stupid Comtrend stuff)
- Wifi works fine on every other AP under Linux
- On Windows (i'm still on dual-boot), connecting through CT635 works fine

I've been looking for information for the past months, and it's becoming a real headache problem. Any suggestion would be greatly appreciated ;)

Pardon my English.
And thanks for years of support.
jdif

Have you tried a nameserver in /etc/resolv.conf? It sounds like you don't; take a look at man resolv.conf and see if that helps.

Are you connecting through Wi-Fi? I have noticed similar behavior when requests are lost sometimes (same ipw2200 card). This mostly happens when I'm quite far from my access point and there are some walls (reinforced concrete) in between. I think wireless is at fault, maybe missing a packet or something similar. Pressing stop and reload fixes the problem. You could try a wired connection and see if it works. Then you would at least know better what is or is not a problem.

Ok I eventually solved this, after many research.

Here it is : http://proj.sunet.se/E2E/tcptune.html

Apparently the comtrend modems (not only the CT635 model) don't
accept large tcp receive window, a paramater than can be tweaked this way:
echo [min_val] [default_val] [max_val] > /proc/sys/net/core/tcp_rmem

This had to do with the MTU as I suspected ; lowering it manually wasn't enough though.
(if a tcp/ip guru has some explanations about this...)

Thanks for your help nonetheless tronayne :) (resolv.conf was ok).

Hope this helps other distressed users like me during the past months.

cheers
jdif

I wolud be very grateful if you could write how big number you wrote, because I have that comtrend too

echo 4096 23360 65534 > /proc/sys/net/ipv4/tcp_rmem

Glad if it can help !

Regards,
jdifslack

If my memory serves me right. Type "about:config" and search for ipv6 and turn it off. That affected me one time. Hope that helps.

i need to read posts all the way.