I have a very odd problem connecting to some websites from my CentOS 5 box
Target websites: www.connecttech.com www.3ware.com (two of my HW vendors)
I can usually get some kind of response, but if the content (download or page itself) is larger in size (downloads never pass 100K), then it hangs...
When I fire-up wireshark, I get a lot of ougoing highlighted Checksum Errored packets but I don't know what's causing it... Here's what I've eliminated thus far:
- Websites are up and responsive - Cable(s) is fine - Network drop is fine - I put myself behind a firewall to make sure it wasn't my network - Network card has been switched - Driver has been switched - Removed any firewall - wget has problems as well - Other computers on the same network work fine.
Sites like maps.google.com work just fine... I'm open to any suggestion at this point.
I'm completely lost.
- G.
semi linux wrote:
I have a very odd problem connecting to some websites from my CentOS 5 box
Target websites: www.connecttech.com www.3ware.com (two of my HW vendors)
I can usually get some kind of response, but if the content (download or page itself) is larger in size (downloads never pass 100K), then it hangs...
When I fire-up wireshark, I get a lot of ougoing highlighted Checksum Errored packets but I don't know what's causing it... Here's what I've eliminated thus far:
- Websites are up and responsive
- Cable(s) is fine
- Network drop is fine
- I put myself behind a firewall to make sure it wasn't my network
- Network card has been switched
- Driver has been switched
- Removed any firewall
- wget has problems as well
- Other computers on the same network work fine.
Sites like maps.google.com work just fine... I'm open to any suggestion at this point.
I'm completely lost.
- G.
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
When you say network drop is fine does that mean from the switch to your computer? Have you tried a different port on your switch?
On 9/20/07, James A. Peltier jpeltier@cs.sfu.ca wrote:
semi linux wrote:
I have a very odd problem connecting to some websites from my CentOS 5 box
Target websites: www.connecttech.com www.3ware.com (two of my HW vendors)
I can usually get some kind of response, but if the content (download or page itself) is larger in size (downloads never pass 100K), then it hangs...
When I fire-up wireshark, I get a lot of ougoing highlighted Checksum Errored packets but I don't know what's causing it... Here's what I've eliminated thus far:
- Websites are up and responsive
- Cable(s) is fine
- Network drop is fine
- I put myself behind a firewall to make sure it wasn't my network
- Network card has been switched
- Driver has been switched
- Removed any firewall
- wget has problems as well
- Other computers on the same network work fine.
Sites like maps.google.com work just fine... I'm open to any suggestion at this point.
I'm completely lost.
- G.
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
When you say network drop is fine does that mean from the switch to your computer? Have you tried a different port on your switch?
I've used my laptop on the same network drop... I've changed from port A to B in this cube and I've tried A and B in the cube next to me... all four ports produce the same result with the system but work fine with my laptop.
When you say network drop is fine does that mean from the switch to your computer? Have you tried a different port on your switch?
I've used my laptop on the same network drop... I've changed from port A to B in this cube and I've tried A and B in the cube next to me... all four ports produce the same result with the system but work fine with my laptop.
What if you boot with a CentOS 5 LiveCD, CentOS 4 LiveCD, or Knoppix on your system?
Barry
semi linux spake the following on 9/20/2007 4:59 PM:
On 9/20/07, James A. Peltier jpeltier@cs.sfu.ca wrote:
semi linux wrote:
I have a very odd problem connecting to some websites from my CentOS 5 box
Target websites: www.connecttech.com www.3ware.com (two of my HW vendors)
I can usually get some kind of response, but if the content (download or page itself) is larger in size (downloads never pass 100K), then it hangs...
When I fire-up wireshark, I get a lot of ougoing highlighted Checksum Errored packets but I don't know what's causing it... Here's what I've eliminated thus far:
- Websites are up and responsive
- Cable(s) is fine
- Network drop is fine
- I put myself behind a firewall to make sure it wasn't my network
- Network card has been switched
- Driver has been switched
- Removed any firewall
- wget has problems as well
- Other computers on the same network work fine.
Sites like maps.google.com work just fine... I'm open to any suggestion at this point.
I'm completely lost.
- G.
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
When you say network drop is fine does that mean from the switch to your computer? Have you tried a different port on your switch?
I've used my laptop on the same network drop... I've changed from port A to B in this cube and I've tried A and B in the cube next to me... all four ports produce the same result with the system but work fine with my laptop.
` Then it has to be the hardware/driver interactions. Or the box has some kind of interference problem. Do you have a power supply you could try? It could be a faulty earth ground on the box or in PS that is causing stray EMF. Your lappy would be OK because it is separated from the ground problem. Since you moved the box, I doubt it is the bldg. wiring.
semi linux spake the following on 9/20/2007 4:31 PM:
I have a very odd problem connecting to some websites from my CentOS 5 box
Target websites: www.connecttech.com www.3ware.com (two of my HW vendors)
I can usually get some kind of response, but if the content (download or page itself) is larger in size (downloads never pass 100K), then it hangs...
When I fire-up wireshark, I get a lot of ougoing highlighted Checksum Errored packets but I don't know what's causing it... Here's what I've eliminated thus far:
- Websites are up and responsive
- Cable(s) is fine
- Network drop is fine
- I put myself behind a firewall to make sure it wasn't my network
- Network card has been switched
- Driver has been switched
- Removed any firewall
- wget has problems as well
- Other computers on the same network work fine.
Sites like maps.google.com work just fine... I'm open to any suggestion at this point.
I'm completely lost.
- G.
Have you eliminated interference from electrical sources? Tried another computer on that cable?
On 9/20/07, Scott Silva ssilva@sgvwater.com wrote:
semi linux spake the following on 9/20/2007 4:31 PM:
I have a very odd problem connecting to some websites from my CentOS 5 box
Target websites: www.connecttech.com www.3ware.com (two of my HW vendors)
I can usually get some kind of response, but if the content (download or page itself) is larger in size (downloads never pass 100K), then it hangs...
When I fire-up wireshark, I get a lot of ougoing highlighted Checksum Errored packets but I don't know what's causing it... Here's what I've eliminated thus far:
- Websites are up and responsive
- Cable(s) is fine
- Network drop is fine
- I put myself behind a firewall to make sure it wasn't my network
- Network card has been switched
- Driver has been switched
- Removed any firewall
- wget has problems as well
- Other computers on the same network work fine.
Sites like maps.google.com work just fine... I'm open to any suggestion at this point.
I'm completely lost.
- G.
Have you eliminated interference from electrical sources? Tried another computer on that cable?
Yep... my WinXP laptop is sitting right next to the machine and I can switch the cable over to it w/o problem.
On Thu, 20 Sep 2007 at 4:31pm, semi linux wrote
I have a very odd problem connecting to some websites from my CentOS 5 box
Target websites: www.connecttech.com www.3ware.com (two of my HW vendors)
I can usually get some kind of response, but if the content (download or page itself) is larger in size (downloads never pass 100K), then it hangs...
I had an odd issue with an FC6 laptop on a hotel wireless network where any encrypted traffic (ssh, https) would hang after a certain amount. The fix was to turn off TCP window scaling (echo 0 > /proc/sys/net/ipv4/tcp_window_scaling). Some googling revealed that some routers have issues with TCP window scaling - I don't know why it only affected encrypted traffic in my case, but the fix may be worth a shot for you.
On 9/20/07, Joshua Baker-LePain jlb17@duke.edu wrote:
On Thu, 20 Sep 2007 at 4:31pm, semi linux wrote
I have a very odd problem connecting to some websites from my CentOS 5 box
Target websites: www.connecttech.com www.3ware.com (two of my HW vendors)
I can usually get some kind of response, but if the content (download or page itself) is larger in size (downloads never pass 100K), then it hangs...
I had an odd issue with an FC6 laptop on a hotel wireless network where any encrypted traffic (ssh, https) would hang after a certain amount. The fix was to turn off TCP window scaling (echo 0 > /proc/sys/net/ipv4/tcp_window_scaling). Some googling revealed that some routers have issues with TCP window scaling - I don't know why it only affected encrypted traffic in my case, but the fix may be worth a shot for you.
-- Joshua Baker-LePain QB3 Shared Cluster Sysadmin UCSF
Wicked! that worked... How weird... I'm going to have to look this up and read about it... it seems weird that the kernel would have it on by default if it's as common as it seems to me.
Thanks a million!
You don't happen to have any links of where you found this, do you?
- G
On Thu, 20 Sep 2007 at 5:04pm, semi linux wrote
Wicked! that worked... How weird... I'm going to have to look this up and read about it... it seems weird that the kernel would have it on by default if it's as common as it seems to me.
Thanks a million!
You don't happen to have any links of where you found this, do you?
Here's one:
http://lwn.net/Articles/92727/
Bottom line is that the behavior is a result of broken routers, and the kernel leaves it enabled because it *should* work.
In article alpine.LRH.0.9999.0709202012480.12238@hogwarts.egr.duke.edu, Joshua Baker-LePain jlb17@duke.edu wrote:
On Thu, 20 Sep 2007 at 5:04pm, semi linux wrote
Wicked! that worked... How weird... I'm going to have to look this up and read about it... it seems weird that the kernel would have it on by default if it's as common as it seems to me.
Thanks a million!
You don't happen to have any links of where you found this, do you?
Here's one:
http://lwn.net/Articles/92727/
Bottom line is that the behavior is a result of broken routers, and the kernel leaves it enabled because it *should* work.
Would be interesting to know what make/model of router the original poster is using, that exhibited this problem, and which firmware version.
Unless the problem is in his ISP....
Cheers Tony
On 9/21/07, Tony Mountifield tony@softins.clara.co.uk wrote:
In article alpine.LRH.0.9999.0709202012480.12238@hogwarts.egr.duke.edu, Joshua Baker-LePain jlb17@duke.edu wrote:
On Thu, 20 Sep 2007 at 5:04pm, semi linux wrote
Wicked! that worked... How weird... I'm going to have to look this up and read about it... it seems weird that the kernel would have it on by default if it's as common as it seems to me.
Thanks a million!
You don't happen to have any links of where you found this, do you?
Here's one:
http://lwn.net/Articles/92727/
Bottom line is that the behavior is a result of broken routers, and the kernel leaves it enabled because it *should* work.
Would be interesting to know what make/model of router the original poster is using, that exhibited this problem, and which firmware version.
Unless the problem is in his ISP....
Cheers Tony
It's further up the line... remember, some websites work, others don't... I suppose it depends on the amount of data coming from the remote site, but everything internal works great and the bigger sites, like google, yahoo, mapquest, etc. all work fine... it's the smaller sites that I had problems with... Believe me, I wish I knew when this problem was but I don't think it's any of the networking gear here in the office...
Thanks to everyone who replied... I would have been searching for weeks on this one.
- G.
-
Barry Brimer -
James A. Peltier -
Joshua Baker-LePain -
Scott Silva -
semi linux -
tony＠softins.clara.co.uk