[c-nsp] strange behavior over MPLS network - remote desktop won't work

Peter Rathlev peter at rathlev.dk
Mon Jun 1 06:35:50 EDT 2009


On Sun, 2009-05-31 at 19:54 -0400, Chris Hale wrote:
> ping do-not-fragment detail size 1473 192.168.3.254
> PING 192.168.3.254 (192.168.3.254): 1473 data bytes
> ping: sendto: Message too long
...
> What does that indicate to you?  1472 + VLAN tag plus MPLS < 1500?

To me this indicates that the Juniper doesn't wan't to send the packet.
As others mentioned 1472 is the largest ICMP payload to expect on a
regularr 1500 byte MTU link.

The "sendto: Message too long" is what I would assume if the IP stack of
the sending host refuses to accept the packet. So the packet never
leaves the CE.

Regards,
Peter




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