Hello,
I just found the discussion https://community.sophos.com/utm-firewall/f/general-discussion/115541/l2tp-vpn-dropping-traffic/416329
My problem sounds similar:
Sporadically the traffic through L2TP over IPSEC (Road warrior) gets lost.
Today the problem appeared:
l2tp tunnel (at client and utm side) was active, I dis-/reconnected the tunnel without success
the Clients ( at least 3 of 5) were not able to rdp to the internal terminalserver anymore
I checked with 1 client: no ping to no internal address,
of course also no rdp access to internal machine
disconnect/reconnect l2tp vpn: no success
timeout in nslookup (internal dns-server) BUT the firewall log shows successful Port 53 connect to the dns-server.
I connected this client via ssl-vpn-client => oK, everything worked (ping, dns, rdp)
I had nothing changed in the internal net.
Then I deactivated/reactivated the L2TP-over-IPsec remote access => oK, the l2tp clients were again able to connect to their internal ressources.
The only thing I found in IPSec-VPN log were messages: not enough room in input packet for ISAKMP Message
but those messages appear also now, when everything seems to be running normal.
This happens every 2 or 3 weeks, so I'm not able to test anything in short time.
Did anybody ever solve this?
UTM Release 9.705-3 at Sophos SG135
actual runtime: 44 days
regards
Uwe
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