From: SonicSS99 (sonicsol@xxxxxxxxxxxxxx)
Date: Wed Feb 06 2002 - 23:08:31 GMT-3
Also, you can regedit the PC/Server per:
http://support.microsoft.com/default.aspx?scid=%2fsearch%2fviewDoc.aspx%3fdocID
%3dKC.Q120642%26dialogID%3d5842896%26iterationID%3d1%26sessionID%3danonymous%7c
5174860
to code the MTU before it hits the router.
The MTU on the GRE tunnel is controlled by the physical. With GRE
encapsulation, the size is 1524, due to the extra encap header. Therefore,
set the Ethernet to 1476 before adding the 'tunnel source x.x.x.x'
statement to the config. The encap mode can also be changed to "tunnel
mode ipip" to fix this issue.
The last method is to use PBR. (http://www.cisco.com/warp/public/105/56.html)
interface ethernet0
...
ip policy route-map clear-df \
!
!
route-map clear-df permit 10
match ip address 101
set ip df 0
!
!
access-list 101 permit tcp 10.1.3.0 0.0.0.255 any
David Steinke, CCNP/CCDP
sonic@cisco.com
At 07:53 PM 2/6/2002 -0500, Hansang Bae wrote:
>At 10:41 AM 2/6/2002 +0000, atul pawar wrote:
>>I am having problem testing one application across frame relay using
>>IPSEC. The router drops the packet as the size is more than 1500. The
>>router sees DF bit set on the incoming packets and drops it. I have seen
>>following url on Cisco
>>http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t
/122t2/ftdfipsc.htm
>>But for this I need IOS upgrade. Is there any other trick to clear the DF
>>bit?
>>Kind Regards,
>
>
>You have a few choices:
>
>1) Upgrade the IOS (which isn't an option for you
>2) Decrease the MTU on the end user PCs
>3) Increse the IP MTU on the GRE tunnel (if used)
> There a some consequences so do a little research
>4) Allo ICMP Code 3 Type 4 packets through so dynamic path
> mtu-discovery will work.
>
>hsb
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