Hi everyone! So I had a L2TP/IPSEC tunnel via a VPN provider, that was working and has recently started having problems. I’m trying to figure out if this is down to something they changed at their end, or something in one of the later RouterOS releases. I’m currently on RouterOS 6.44beta14
The initial connection is fine;
07:07:18 ipsec,info initiate new phase 1 (Identity Protection): 70.95.93.xx[500]<=>104.237.61.xxx[500]
07:07:19 ipsec,info ISAKMP-SA established 70.95.93.xx[500]-104.237.61.xxx[500] spi:e34571107a98e1cc:06d0dbbedf8c9ba8
07:07:21 l2tp,ppp,info l2tp-out1: authenticated
07:07:22 l2tp,ppp,info l2tp-out1: connected
and then after a random period of time (can be anywhere from 30 mins to 3hrs+) , I see this is the log;
10:50:13 l2tp,ppp,info l2tp-out1: terminating... - hungup
10:50:13 l2tp,ppp,info l2tp-out1: disconnected
10:50:13 l2tp,ppp,info l2tp-out1: initializing...
10:50:13 l2tp,ppp,info l2tp-out1: connecting...
10:50:13 l2tp,ppp,info l2tp-out1: authenticated
10:50:13 l2tp,ppp,info l2tp-out1: connected
The L2TP interface is up, the SA’s look to be there - but it doesnt pass any traffic. If I manually drop and restablish the connection, then it works fine again for a while. I can’t easily tell if the ‘hungup’ is from my end or the remote server?
Running pretty much a standard config - due to the remote provider, I can’t use PFS but everything else is pretty standard
/ip ipsec proposal
set [ find default=yes ] auth-algorithms=sha512,sha256,sha1 pfs-group=none
Basic L2TP interface
/interface l2tp-client
add add-default-route=yes allow=mschap2 connect-to=104.237.61.xxx ipsec-secret=mysecret keepalive-timeout=disabled max-mru=1400 max-mtu=1400 name=l2tp-out1 password=yyyyyyy use-ipsec=yes user=zzzzzzz
As I say, I havent changed anything recently in the config - so wondered if this rang any bells with anyone who has an IPSEC peer ‘sort of working’ 
, or could suggest the next layer of debugging.