My customer has a problem with windows logon.
Windows calculates the bandwidth of link by sending ICMP Packets in different size.
The ICMP packets will already be fragmented (but with NO DF set) by the server if they are greater than 1480 bytes.
If these fragmented packets (with NO DF bit set) are further sent across the DMVPN tunnel to the client,
the router again fragments the âalready fragmentedâ packets because the max. MTU on tunnel is 1436 bytes.
This does not work properly.
We could fix this by setting the max. MTU on all Servers and Clients and on the routers on the way to max. 1436bytes,
but this will be some additional work and a change on the existing production systems, which the customer would like to avoid if possible.
Is there any other option to fix this by configuring the router?
questions for example are:
-is there a config. parameter at the DMVPN routers that can be set in order to fix the issue that the already fragmented
ICMP packet to 1480 will be properly fragmented to 1436 and reassembled @ the remote router again?
-is there any parameter to configure something link MTU path discovery (as we have for TCP) for the ICMP packets sent by the server?
thanks in advance,