On Wed, 30 Jul 2008 01:52:06 +0100 "j t" <mark473@xxxxxxxxx> wrote: > Hi all. > > I have a strange networking problem. If I run (on linux): > wget http://ocp.com.com/ad.js > then wget just times out, retries, and eventually gives up, thus: > > > $ wget http://ocp.com.com/ad.js > --2008-07-29 20:15:16-- http://ocp.com.com/ad.js > Resolving ocp.com.com... 216.239.122.193 > Connecting to ocp.com.com|216.239.122.193|:80... connected. > HTTP request sent, awaiting response... Read error (Connection timed > out) in headers. > Retrying. > > --2008-07-29 20:30:17-- (try: 2) http://ocp.com.com/ad.js > Connecting to ocp.com.com|216.239.122.193|:80... connected. > HTTP request sent, awaiting response... Read error (Connection timed > out) in headers. > Retrying. > > --2008-07-29 20:45:19-- (try: 3) http://ocp.com.com/ad.js > Connecting to ocp.com.com|216.239.122.193|:80... connected. > HTTP request sent, awaiting response... Read error (Connection timed > out) in headers. > Retrying. > ... > ... > --2008-07-30 01:02:43-- (try:20) http://ocp.com.com/ad.js > Connecting to ocp.com.com|216.239.122.193|:80... connected. > HTTP request sent, awaiting response... Read error (Connection timed > out) in headers. > Giving up. > > > > If I change my mtu from 1500 to 1499, then the same wget command > succeeds almost instantly, thus: > > > $ wget http://ocp.com.com/ad.js > --2008-07-29 20:28:13-- http://ocp.com.com/ad.js > Resolving ocp.com.com... 216.239.122.193 > Connecting to ocp.com.com|216.239.122.193|:80... connected. > HTTP request sent, awaiting response... 200 OK > Length: 1069 (1.0K) [text/html] > Saving to: `ad.js' > > 100%[======================================>] 1,069 --.-K/s in 0s > > 2008-07-29 20:28:14 (89.0 MB/s) - `ad.js' saved [1069/1069] > > > I've tried Debian Etch (with 2.6.18) and Debian Lenny (with 2.6.24) > and the problem remains with both kernel versions. I get the same > problem (under Linux) using various http clients: wget, epiphany and > iceweasel (firefox). If, however, I reboot into Windows XP and use a > native wget (from http://users.ugent.be/~bpuype/wget/) or firefox, the > problem does not occur. > > The final twist in the tale is that I can force my router (using a > dhcp option) to get a public-facing IP on either the 78.105.x.x > network or the 93.96.x.x network, and the problem only ever occurs > when I'm connected to the 78.105.x.x network. > > So, to recap, if my workstation is booted into linux (instead of > windows XP) and my ISP has given my router an external ip address of > 78.105.x.x (instead of 93.96.x.x), then I can't retrieve the contents > at the url http://ocp.com.com/ad.js (regardless of which http client I > use). > > I think my next step is to run tcpdump on my router and dump the tcp > flows in both cases and then compare, but I'd love to know if anyone > reading this has any better ideas (I've already spent about 3 weeks > trying to get this far - if there's a shortcut, I'd be very grateful > if someone would tell me). > > Thanks in advance for any help you can offer, Jaime. > > PS: In case you're wondering why I'm interested in that url, it's > included in http://www.osnews.com homepage (which doesn't load for me, > and I've managed to trace it back to that ad.js url). You may be suffering with a site that has a window scaling problem. This is due to some firewall or other middlebox that can't keep track of window scaling properly. More information is in: http://lwn.net/Articles/92727/ -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
