Open Stack

Hi,

I recently observed a strange behaviour with L3 Quantum routing 
(Openvswitch setup with Provider Router). A simple curl to an external 
website is sometimes failing due to packet size  :

     192.168.10.3 > X.X.X.X: ICMP 192.168.10.3 unreachable - need to 
frag (mtu 1454), length 556
     IP (tos 0x0, ttl 48, id 25918, offset 0, flags [DF], proto TCP (6), 
length 1500)

Only changing the VM MTU to 1454 does the trick ('ifconfig eth0 mtu 1454').

For info, 192.168.10.3 is the floating IP bound to 10.0.0.4 (private IP).

I can't provide the URL for reproducing, as the external website is 
actually an external corporate webservice.
Do you have any idea on what could be the root cause, and how to fix it ?

Thanks,
-Sylvain