Re: [SQU] More on WCCP and truncated GRE packets. --HELP

At 03:23 AM 14/12/2000 -0600, Nathan Lewis wrote:
>>Your problem very much looks like the IOS problem another user found
>>some month ago.
>>
>>He found WCCP a Cisco 2621 gave truncated packets when using certain IOS
>>version, sometimes even down to the IP header of the encapsulated
>>packet.
>>
>> From trying different IOS versions he found that:
>> IOS 12.1-3a did not work and gave truncated packets
>> IOS 12.0-7T and IOS 12.1-5 worked fine.
>
>Lincoln - this seems like a viable alternative to the MTU problem (since
>it is the actual GRE packet which is truncated, not the underlying www
>request, as would be implied by an MTU problem). I think I requested the
>latest version of IOS for my Cisco 2610. Would I have to go back down to
>12.0, or is there a 12.1(5)T available for the 2600 series, as is implied
>by the above message?

i can't comment on the tcpdump traces Henrik included; if they're generated
from tcpdump running on the same host as the ip_wccp module then we don't
know for sure if the information is correct. (and only partial traces are
posted).

i'm not aware of any issues with 12.1(3). in fact, that is the exact
release i run on my 2621 here.

about the only possibility i see is under cisco bug id "CSCdr67139" (you
can track this on CCO).
basically, it is:

  This bug was introduced by CSCdp56613. It applies to low-end systems
running IOS.
  It occurs in the fast switching path when WCCP is enabled. It happens because
  WCCP adds a GRE header to redirected packets and this is not accounted for
  in the fast switching path. The problem will also apply to any outgoing
feature
  which involves adding an IP header to a packet.

  CSCdp56613 had been integrated into the following versions:
         12.1(1.4)
         12.0(10.03)S
         12.1(1.4)T
         12.0(10.3)SC
         12.0(11)
         12.0(11.1)
         12.1(1)DB
         12.1(1)DC
         12.0(11.3)S

  so this problem will affect all low-end systems running these versions.
  the fix has been integrated into the following versions:
         12.1(3.4)
         12.1(3.4)T
         12.1(3.4)AA
         12.1(3.4)PI
         12.0(12.6)
         12.0(12.6)S
         12.0(12.6)W05(18.00.54)
         12.0(12.6)SC

cheers,

lincoln.

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