06-24-2010 02:25 PM - edited 03-11-2019 11:03 AM
I have a website that I cannot access via any of the Cisco 877 routers I have installed, 10 in total. When I try to access this url
The page does not display after a period of about 3 minutes waiting for the browser to retry. The question is, is there a maximum length on a url that Cisco implement in the Advanced Security IOS for this model?
I have tried the url on a Cisco 1841 and it works fine with a very similar config.
Im sorry if this isnt the right place for this post, please redirect me if there is a better forum for this!
Thanks
Kyle
06-24-2010 02:29 PM
This problem might be related with mtu maybe or mss. from the 800 routers... does the traffic pass a GRE tunnel?
06-24-2010 02:31 PM
It doesnt no, but I do have an IPSEC tunnel to another 877 at a remote site. I set the mss on the ATM0.1 interface to 1300 on a ADSL2 circuit, this has improved the IPSEC tunnel significantly in terms of fragmentation.
I will try upping the mss back to 1452 again and test. Thanks
06-24-2010 02:45 PM
I have just tested further and the issue seems to only fail from Windows XP, I have tested from a Windows 2008 Server and this is successful. I have changed the command on the ATM0.1 interface to
no ip tcp adjust-mss 1300
and the issue still occurs. Its really making me think this one as the site is a government website and worked for my customer for months until last thursday so I can only think that something changed at the website level or hosting otherwise it wouldnt have worked before.
06-24-2010 02:52 PM
Go ahead and do a debug for ICMP .. If you see this messange
ICMP: dst (x.x.x.x) frag. needed and DF set unreachable sent to x.x.x.x this is a fragmentation issue.
06-24-2010 03:07 PM
Thanks, I will try that tomorrow. I just can't work out why it works on Windows 2008 and not Windows XP behind the same router.
--
Kyle Heath
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