HI!
I have organized VPN L2TP tunnel between hAP ac^2 (server, white IP) and RB750Gr3 (client, 4G modem). More than a year everything worked fine and tunnel was automatically restoring itself when the connection was dropped on any side. But last time something went wrong, please give me a tip what the reason can be. I'm very bad at tunneling and L2TP(( Here this the log of th sever, the same occurs continuously (85.140.16.198:61259 - client, ***.**.***.***:**** - server):
4 Mar/20/2020 10:51:23 memory l2tp, debug, packet rcvd control message from 85.140.16.198:61259 to ***.**.***.***:****
5 Mar/20/2020 10:51:23 memory l2tp, debug, packet tunnel-id=0, session-id=0, ns=0, nr=0
6 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Message-Type=SCCRQ
7 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
8 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
9 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
10 Mar/20/2020 10:51:23 memory l2tp, debug, packet Firmware-Revision=0x1
11 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Host-Name="MikroTik"
12 Mar/20/2020 10:51:23 memory l2tp, debug, packet Vendor-Name="MikroTik"
13 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=8
14 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Receive-Window-Size=4
15 Mar/20/2020 10:51:23 memory l2tp, info first L2TP UDP packet received from 85.140.16.198
16 Mar/20/2020 10:51:23 memory l2tp, debug tunnel 136 entering state: wait-ctl-conn
17 Mar/20/2020 10:51:23 memory l2tp, debug, packet sent control message to 85.140.16.198:61259 from ***.**.***.***:****
18 Mar/20/2020 10:51:23 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=0, nr=1
19 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Message-Type=SCCRP
20 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
21 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
22 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
23 Mar/20/2020 10:51:23 memory l2tp, debug, packet Firmware-Revision=0x1
24 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Host-Name="MikroTik"
25 Mar/20/2020 10:51:23 memory l2tp, debug, packet Vendor-Name="MikroTik"
26 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=136
27 Mar/20/2020 10:51:23 memory l2tp, debug, packet (M) Receive-Window-Size=4
28 Mar/20/2020 10:51:24 memory l2tp, debug, packet sent control message to 85.140.16.198:61259 from ***.**.***.***:****
29 Mar/20/2020 10:51:24 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=0, nr=1
30 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Message-Type=SCCRP
31 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
32 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
33 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
34 Mar/20/2020 10:51:24 memory l2tp, debug, packet Firmware-Revision=0x1
35 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Host-Name="MikroTik"
36 Mar/20/2020 10:51:24 memory l2tp, debug, packet Vendor-Name="MikroTik"
37 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=136
38 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Receive-Window-Size=4
39 Mar/20/2020 10:51:24 memory l2tp, debug, packet rcvd control message from 85.140.16.198:61259 to ***.**.***.***:****
40 Mar/20/2020 10:51:24 memory l2tp, debug, packet tunnel-id=0, session-id=0, ns=0, nr=0
41 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Message-Type=SCCRQ
42 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
43 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
44 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
45 Mar/20/2020 10:51:24 memory l2tp, debug, packet Firmware-Revision=0x1
46 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Host-Name="MikroTik"
47 Mar/20/2020 10:51:24 memory l2tp, debug, packet Vendor-Name="MikroTik"
48 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=8
49 Mar/20/2020 10:51:24 memory l2tp, debug, packet (M) Receive-Window-Size=4
50 Mar/20/2020 10:51:24 memory l2tp, debug, packet sent control message (ack) to 85.140.16.198:61259 from ***.**.***.***:****
51 Mar/20/2020 10:51:24 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=1, nr=1
52 Mar/20/2020 10:51:25 memory l2tp, debug, packet sent control message to 85.140.16.198:61259 from ***.**.***.***:****
53 Mar/20/2020 10:51:25 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=0, nr=1
54 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Message-Type=SCCRP
55 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
56 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
57 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
58 Mar/20/2020 10:51:25 memory l2tp, debug, packet Firmware-Revision=0x1
59 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Host-Name="MikroTik"
60 Mar/20/2020 10:51:25 memory l2tp, debug, packet Vendor-Name="MikroTik"
61 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=136
62 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Receive-Window-Size=4
63 Mar/20/2020 10:51:25 memory l2tp, debug, packet rcvd control message from 85.140.16.198:61259 to ***.**.***.***:****
64 Mar/20/2020 10:51:25 memory l2tp, debug, packet tunnel-id=0, session-id=0, ns=0, nr=0
65 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Message-Type=SCCRQ
66 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
67 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
68 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
69 Mar/20/2020 10:51:25 memory l2tp, debug, packet Firmware-Revision=0x1
70 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Host-Name="MikroTik"
71 Mar/20/2020 10:51:25 memory l2tp, debug, packet Vendor-Name="MikroTik"
72 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=8
73 Mar/20/2020 10:51:25 memory l2tp, debug, packet (M) Receive-Window-Size=4
74 Mar/20/2020 10:51:25 memory l2tp, debug, packet sent control message (ack) to 85.140.16.198:61259 from ***.**.***.***:****
75 Mar/20/2020 10:51:25 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=1, nr=1
76 Mar/20/2020 10:51:27 memory l2tp, debug, packet sent control message to 85.140.16.198:61259 from ***.**.***.***:****
77 Mar/20/2020 10:51:27 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=0, nr=1
78 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Message-Type=SCCRP
79 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
80 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
81 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
82 Mar/20/2020 10:51:27 memory l2tp, debug, packet Firmware-Revision=0x1
83 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Host-Name="MikroTik"
84 Mar/20/2020 10:51:27 memory l2tp, debug, packet Vendor-Name="MikroTik"
85 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=136
86 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Receive-Window-Size=4
87 Mar/20/2020 10:51:27 memory l2tp, debug, packet rcvd control message from 85.140.16.198:61259 to ***.**.***.***:****
88 Mar/20/2020 10:51:27 memory l2tp, debug, packet tunnel-id=0, session-id=0, ns=0, nr=0
89 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Message-Type=SCCRQ
90 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
91 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
92 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
93 Mar/20/2020 10:51:27 memory l2tp, debug, packet Firmware-Revision=0x1
94 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Host-Name="MikroTik"
95 Mar/20/2020 10:51:27 memory l2tp, debug, packet Vendor-Name="MikroTik"
96 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=8
97 Mar/20/2020 10:51:27 memory l2tp, debug, packet (M) Receive-Window-Size=4
98 Mar/20/2020 10:51:27 memory l2tp, debug, packet sent control message (ack) to 85.140.16.198:61259 from ***.**.***.***:****
99 Mar/20/2020 10:51:27 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=1, nr=1
100 Mar/20/2020 10:51:31 memory l2tp, debug, packet sent control message to 85.140.16.198:61259 from ***.**.***.***:****
101 Mar/20/2020 10:51:31 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=0, nr=1
102 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Message-Type=SCCRP
103 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
104 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
105 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
106 Mar/20/2020 10:51:31 memory l2tp, debug, packet Firmware-Revision=0x1
107 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Host-Name="MikroTik"
108 Mar/20/2020 10:51:31 memory l2tp, debug, packet Vendor-Name="MikroTik"
109 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=136
110 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Receive-Window-Size=4
111 Mar/20/2020 10:51:31 memory l2tp, debug, packet rcvd control message from 85.140.16.198:61259 to ***.**.***.***:****
112 Mar/20/2020 10:51:31 memory l2tp, debug, packet tunnel-id=0, session-id=0, ns=0, nr=0
113 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Message-Type=SCCRQ
114 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
115 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
116 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
117 Mar/20/2020 10:51:31 memory l2tp, debug, packet Firmware-Revision=0x1
118 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Host-Name="MikroTik"
119 Mar/20/2020 10:51:31 memory l2tp, debug, packet Vendor-Name="MikroTik"
120 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=8
121 Mar/20/2020 10:51:31 memory l2tp, debug, packet (M) Receive-Window-Size=4
122 Mar/20/2020 10:51:31 memory l2tp, debug, packet sent control message (ack) to 85.140.16.198:61259 from ***.**.***.***:****
123 Mar/20/2020 10:51:31 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=1, nr=1
124 Mar/20/2020 10:51:39 memory l2tp, debug, packet sent control message to 85.140.16.198:61259 from ***.**.***.***:****
125 Mar/20/2020 10:51:39 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=0, nr=1
126 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Message-Type=SCCRP
127 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
128 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
129 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
130 Mar/20/2020 10:51:39 memory l2tp, debug, packet Firmware-Revision=0x1
131 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Host-Name="MikroTik"
132 Mar/20/2020 10:51:39 memory l2tp, debug, packet Vendor-Name="MikroTik"
133 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=136
134 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Receive-Window-Size=4
135 Mar/20/2020 10:51:39 memory l2tp, debug, packet rcvd control message from 85.140.16.198:61259 to ***.**.***.***:****
136 Mar/20/2020 10:51:39 memory l2tp, debug, packet tunnel-id=0, session-id=0, ns=0, nr=0
137 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Message-Type=SCCRQ
138 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Protocol-Version=0x01:00
139 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Framing-Capabilities=0x1
140 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Bearer-Capabilities=0x0
141 Mar/20/2020 10:51:39 memory l2tp, debug, packet Firmware-Revision=0x1
142 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Host-Name="MikroTik"
143 Mar/20/2020 10:51:39 memory l2tp, debug, packet Vendor-Name="MikroTik"
144 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Assigned-Tunnel-ID=8
145 Mar/20/2020 10:51:39 memory l2tp, debug, packet (M) Receive-Window-Size=4
146 Mar/20/2020 10:51:39 memory l2tp, debug, packet sent control message (ack) to 85.140.16.198:61259 from ***.**.***.***:****
147 Mar/20/2020 10:51:39 memory l2tp, debug, packet tunnel-id=8, session-id=0, ns=1, nr=1
148 Mar/20/2020 10:51:39 memory l2tp, debug tunnel 136 received no replies, disconnecting
149 Mar/20/2020 10:51:39 memory l2tp, debug tunnel 136 entering state: dead