[strongSwan] L2TP/IPSec Connect/Disconnect Problems

[Milen Pankov]

Hi,

I have problems using l2tp/ipsec connections with openswan/xl2tp. Users
using the connection frequently disconnect and after that cannot connect
anymore. Here is a log example from a user that failed to connect after
a disconnect:

2014-08-09 23:20:30: "l2tp"[2422] public_ip:4500 #2738: NAT-Traversal:
received 2 NAT-OA. using first, ignoring others
2014-08-09 23:20:30: "l2tp"[2422] public_ip:4500 #2738: responding to
Quick Mode
2014-08-09 23:20:30: "l2tp"[2422] public_ip:4500 #2738: cannot install
eroute -- it is in use for "l2tp"[2419] public_ip:4500 #2735
2014-08-09 23:20:30: "l2tp"[2422] public_ip:4500: deleting connection
"l2tp" instance with peer public_ip {isakmp=#0/ipsec=#0}
2014-08-09 23:20:32: "l2tp"[2419] public_ip:4500 #2734: Quick Mode I1
message is unacceptable because it uses a previously used Message ID
0x02000000 (perhaps this is a duplicated packet)
2014-08-09 23:20:32: "l2tp"[2419] public_ip:4500 #2734: sending
encrypted notification INVALID_MESSAGE_ID to public_ip:4500
2014-08-09 23:20:35: "l2tp"[2419] public_ip:4500 #2734: Quick Mode I1
message is unacceptable because it uses a previously used Message ID
0x02000000 (perhaps this is a duplicated packet)

Can you help me with this?

Regards,
Milen