30 working l2tp/ipsec tunnels into a RB3011 server
One of them suddenly stops working:
client (a 3011 too) starts and complete phase1 and phase2 (a pair SA installed on both machines) , then it sends control message (three times) to server but this one doesn't receive anything.
Then, client drops the whole connection due to "tunnel xx received no replies, disconnecting"
Only the client side SA with Src.Address <local> and Dst.Address <remote> increases its "Current Bytes" counter (due to starting l2tp session) all other SA have no traffic.
No changes are made on both machines.
Server firewall filter uses the same rules for all clients (that are working) no incoming packets from client are dropped.
Rebooted routerboard and ISP router on both sides, no way.
Both RB are 6.44
Both have public ip address on their WANs
Any suggestion please ?