[strongSwan] RDP over VPN tunnel

[Andreas Muerdter]

Hi list,

I have two VPN tunnels with 3 Server (net2net).

|HostA| --- |HostB|---|HostC|

HostA and HostC is running with strongswan 2.8.11 and Host B is running with strongswan 4.4.1. ICMP between all nets binhind the hosts A,B,C is OK. But when I try to connect via RDP from Net A (HostA) to Net C (HostC) over HostB, the RDP connection will not establish.
The same happens from NET C to NET A over Host B.
But I can connect from Net B to Net A and Net C via RDP without any problems.
It  seems that Host B do not forward all traffic  to the other nets with a higher package size.
It is not a iptables problem, it seem like mtu in the ipsec or someting else.

any ideas?

Regards
Andreas