Hello Folks!
I have a problem which has been ongoing for little more than a year regarding lt2p vpn tunnels.
RoS is a couples of 6.48.3 CHR in one end and various physical mikrotik routers in the other end also running 6.48.3.
At random classic L2TP VPN (no IPsec) tunnels goes down and logs start fill up with "first L2TP UDP package received from"
VPN links goes dow, and is down for a shorter(hours) or longer period(days, weeks..) and then as suddenly it is up again like nothing happened and is up for a shorter or longer time.
I have never been able to track down the issue, disable/enable the L2TP interface at both end did not work, upgrading the mikrotik devices did not work.
All connections are VPN connections, no NAT in between.
Firewalls at both ends accepts UDP port 1701, 500, 4500 and also IPsec-esp, IPsec-ah.
Anyone who have an idea of what this could be or howto fix it ?