Can't load one specific web site

DittoAlex · 09-20-2007, 08:12 PM

OS: Debian Etch 4.0r1

Problem: From this machine, cannot load sfa.osu.edu.

Additional information: Site is up and can be accessed from a Ubuntu machine on my network.

A tcpdump shows that the domain name is resolved, the connection is made, and a few packets are transferred back and forth, but then it just idles until browser timeout.

I have tried faking my useragent as IE, thinking the site may have some silly restriction, but it did not help.

Browsers tried are Firefox 2.0.0.6 and elinks 0.11.1-1.2.

Code:

20:59:51.435520 IP (tos 0x0, ttl  64, id 41781, offset 0, flags [DF], proto: TCP (6), length: 52) myhostname.local.53273 > sfa-web.adm.ohio-state.edu.www: F, cksum 0x7510 (correct), 1589676898:1589676898(0) ack 1112734155 win 46 <nop,nop,timestamp 68900630 0>
20:59:51.482382 IP (tos 0x0, ttl 106, id 9194, offset 0, flags [DF], proto: TCP (6), length: 52) sfa-web.adm.ohio-state.edu.www > myhostname.local.53273: ., cksum 0x8a81 (correct), 1449:1449(0) ack 1 win 65333 <nop,nop,timestamp 31515646 68900630>
20:59:51.486110 IP (tos 0x0, ttl 106, id 9195, offset 0, flags [DF], proto: TCP (6), length: 1500) sfa-web.adm.ohio-state.edu.www > myhostname.local.53273: . 1449:2897(1448) ack 1 win 65333 <nop,nop,timestamp 31515646 68900630>
20:59:51.486144 IP (tos 0x0, ttl  64, id 0, offset 0, flags [DF], proto: TCP (6), length: 40) myhostname.local.53273 > sfa-web.adm.ohio-state.edu.www: R, cksum 0x45b1 (correct), 1589676899:1589676899(0) win 0
20:59:57.981802 IP (tos 0x0, ttl  64, id 23930, offset 0, flags [DF], proto: UDP (17), length: 57) myhostname.local.37986 > DD-WRT.domain: [udp sum ok]  65164+ AAAA? sfa.osu.edu. (29)
20:59:58.029654 IP (tos 0x0, ttl  64, id 0, offset 0, flags [DF], proto: UDP (17), length: 94) DD-WRT.domain > myhostname.local.37986:  65164 q: AAAA? sfa.osu.edu. 1/0/0 sfa.osu.edu. CNAME[|domain]
20:59:58.030049 IP (tos 0x0, ttl  64, id 23943, offset 0, flags [DF], proto: UDP (17), length: 57) myhostname.local.37986 > DD-WRT.domain: [udp sum ok]  39644+ A? sfa.osu.edu. (29)
20:59:58.075482 IP (tos 0x0, ttl  64, id 0, offset 0, flags [DF], proto: UDP (17), length: 110) DD-WRT.domain > myhostname.local.37986:  39644 q: A? sfa.osu.edu. 2/0/0 sfa.osu.edu. CNAME[|domain]
20:59:58.075971 IP (tos 0x0, ttl  64, id 61752, offset 0, flags [DF], proto: TCP (6), length: 60) myhostname.local.53274 > sfa-web.adm.ohio-state.edu.www: S, cksum 0x4101 (correct), 1640672426:1640672426(0) win 5840 <mss 1460,sackOK,timestamp 68902290 0,nop,wscale 7>
20:59:58.114547 IP (tos 0x0, ttl 107, id 9200, offset 0, flags [none], proto: TCP (6), length: 64) sfa-web.adm.ohio-state.edu.www > myhostname.local.53274: S, cksum 0x47f8 (correct), 4014878759:4014878759(0) ack 1640672427 win 16384 <mss 1460,nop,wscale 0,nop,nop,timestamp 0 0,nop,nop,sackOK>
20:59:58.114597 IP (tos 0x0, ttl  64, id 61753, offset 0, flags [DF], proto: TCP (6), length: 52) myhostname.local.53274 > sfa-web.adm.ohio-state.edu.www: ., cksum 0x66de (correct), 1:1(0) ack 1 win 46 <nop,nop,timestamp 68902300 0>
20:59:58.115135 IP (tos 0x0, ttl  64, id 61754, offset 0, flags [DF], proto: TCP (6), length: 254) myhostname.local.53274 > sfa-web.adm.ohio-state.edu.www: P 1:203(202) ack 1 win 46 <nop,nop,timestamp 68902300 0>
20:59:58.735695 IP (tos 0x0, ttl  64, id 61755, offset 0, flags [DF], proto: TCP (6), length: 254) myhostname.local.53274 > sfa-web.adm.ohio-state.edu.www: P 1:203(202) ack 1 win 46 <nop,nop,timestamp 68902455 0>
20:59:58.786679 IP (tos 0x0, ttl 107, id 9208, offset 0, flags [DF], proto: TCP (6), length: 52) sfa-web.adm.ohio-state.edu.www > myhostname.local.53274: ., cksum 0x759e (correct), 2897:2897(0) ack 203 win 65333 <nop,nop,timestamp 31515719 68902290>
21:00:34.109214 IP (tos 0x0, ttl  64, id 61756, offset 0, flags [DF], proto: TCP (6), length: 52) myhostname.local.53274 > sfa-web.adm.ohio-state.edu.www: F, cksum 0x42ed (correct), 203:203(0) ack 1 win 46 <nop,nop,timestamp 68911298 0>
21:00:34.147949 IP (tos 0x0, ttl 107, id 9216, offset 0, flags [none], proto: TCP (6), length: 52) sfa-web.adm.ohio-state.edu.www > myhostname.local.53274: ., cksum 0x5a4e (correct), 525:525(0) ack 204 win 65333 <nop,nop,timestamp 31516074 68911298>
21:00:34.148927 IP (tos 0x0, ttl 107, id 9217, offset 0, flags [none], proto: TCP (6), length: 576) sfa-web.adm.ohio-state.edu.www > myhostname.local.53274: . 525:1049(524) ack 204 win 65333 <nop,nop,timestamp 31516074 68911298>
21:00:34.148947 IP (tos 0x0, ttl  64, id 0, offset 0, flags [DF], proto: TCP (6), length: 40) myhostname.local.53274 > sfa-web.adm.ohio-state.edu.www: R, cksum 0x2093 (correct), 1640672630:1640672630(0)

GrapefruiTgirl · 09-20-2007, 08:20 PM

Have you tried through a free proxy server?
Just Google 'Free proxy server' and pick from the list. I like 'freetoview.net' for its simplicity.
If it works, I'm not really sure what it proves or disproves, except *maybe* your IP might be blacklisted for some unknown and possibly erronious reason.. It's been known to happen.
Keep us posted

DittoAlex · 09-20-2007, 08:25 PM

Quote:

Originally Posted by GrapefruiTgirl

Have you tried through a free proxy server?
Just Google 'Free proxy server' and pick from the list. I like 'freetoview.net' for its simplicity.
If it works, I'm not really sure what it proves or disproves, except *maybe* your IP might be blacklisted for some unknown and possibly erronious reason.. It's been known to happen.
Keep us posted

I'm going through a NAT switch, so the machine on my network which works shares the same WAN IP.

GrapefruiTgirl · 09-20-2007, 08:45 PM

Hmm.. Well, I've never heard of a blacklisted MAC address.. But did you try a proxy anyway? Who knows..

jcliburn · 09-21-2007, 07:45 PM

This will get you going...

Code:

$ su -c 'echo 0 > /proc/sys/net/ipv4/tcp_window_scaling'

To make it permanent:

Code:

$ su -c 'sysctl -w net.ipv4.tcp_window_scaling = 0'

DittoAlex · 09-21-2007, 07:59 PM

Quote:

Originally Posted by jcliburn

This will get you going...

Code:

$ su -c 'echo 0 > /proc/sys/net/ipv4/tcp_window_scaling'

To make it permanent:

Code:

$ su -c 'sysctl -w net.ipv4.tcp_window_scaling = 0'

It worked perfectly.

Can you please elaborate on the technical details as to why this worked and how you knew it was the solution?

DittoAlex · 09-21-2007, 08:02 PM

Quote:

Originally Posted by GrapefruiTgirl

Hmm.. Well, I've never heard of a blacklisted MAC address.. But did you try a proxy anyway? Who knows..

It wouldn't have been a blacklisted MAC, but strangely enough, it did work through tor+privoxy.

This was before the solution above was used to fix it.

jcliburn · 09-21-2007, 08:16 PM

Quote:

Originally Posted by DittoAlex

Can you please elaborate on the technical details as to why this worked and how you knew it was the solution?

See this link for the gory details. http://lwn.net/Articles/92727/

Bottom line is that Ohio State apparently uses an aging router that doesn't follow RFC 1323.

I recognized your symptoms from previous experience.

DittoAlex · 09-21-2007, 08:17 PM

Thank you.

jcliburn · 09-21-2007, 08:20 PM

You're quite welcome. Best of luck in school.

GrapefruiTgirl · 09-21-2007, 10:03 PM

Very interesting tidbit re: the old router. Glad I followed up on this! Always something new...

Tristan Schmelcher · 10-03-2007, 11:53 PM

I'd just like to say that this just helped me out a lot. I had the very same problem while staying at a hotel this week (Hotel Avante in Mountain View, for anyone else googling the same problem

) and it virtually prevented me from doing anything useful on the Internet. I couldn't even SSH or VNC into the computer that I left at home to deal with this very sort of crisis! But this fix works perfectly, as mentioned.

I should note though that I tried a Windows laptop and it didn't need any special configuration to work. Shouldn't we find that embarrassing?