IPSEC/L2TP VPN not establishing from Windows 10

Post your questions about SoftEther VPN software here. Please answer questions if you can afford.
Post Reply
myron.s
Posts: 2
Joined: Sun Nov 29, 2020 4:38 pm

IPSEC/L2TP VPN not establishing from Windows 10

Post by myron.s » Sat Jun 19, 2021 11:23 am

I need some help. For several weeks I've not managed to to get a Windows Laptop to connect to SoftEther VPN Server Developer Edition Version 5.01 Build 9674 running on a NAS operating on Linux 4.14.22 #1 SMP Mon Dec 21 03:06:55 UTC 2020 Build-26 x86_64 GNU/Linux.

I can VPN from Android phones so IPSEC is working and it looks like the handshake just suddenly terminates when it seems like the connection is established. I'm getting round this by using the SoftEther VPN client so it's not a major issue for me, but I would like to know what's causing this to fail. I did used to use just the built-in Windows 10 VPN client, but then for some reason a number of weeks ago it suddenly failed to connect without me changing any settings on either the Windows client or the Linux SoftEther VPN server.

This is the connection sequence that is recorded:

Code: Select all

Public IP address replaced with 192.168.0.1 for this report.

2021-06-19 10:46:33.152 IPsec Client 15760 (192.168.0.1:500 -> 0.0.0.0:500): A new IPsec client is created.
2021-06-19 10:46:33.152 IPsec IKE Session (IKE SA) 8 (Client: 15760) (192.168.0.1:500 -> 0.0.0.0:500): A new IKE SA (Main Mode) is created. Initiator Cookie: 0x6B44EE0FAFD23DA6, Responder Cookie: 0xAE520B55C57BA858, DH Group: MODP 2048 (Group 14), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 256 bits, Lifetime: 4294967295 Kbytes or 28800 seconds
2021-06-19 10:46:33.213 IPsec Client 15760 (192.168.0.1:4500 -> 0.0.0.0:4500): The port number information of this client is updated.
2021-06-19 10:46:33.213 IPsec Client 15760 (192.168.0.1:4500 -> 0.0.0.0:4500): 
2021-06-19 10:46:33.213 IPsec IKE Session (IKE SA) 8 (Client: 15760) (192.168.0.1:4500 -> 0.0.0.0:4500): This IKE SA is established between the server and the client.
2021-06-19 10:46:33.223 IPsec IKE Session (IKE SA) 8 (Client: 15760) (192.168.0.1:4500 -> 0.0.0.0:4500): The client initiates a QuickMode negotiation.
2021-06-19 10:46:33.223 IPsec ESP Session (IPsec SA) 9 (Client: 15760) (192.168.0.1:4500 -> 0.0.0.0:4500): A new IPsec SA (Direction: Client -> Server) is created. SPI: 0x71EE0F53, DH Group: (null), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 250000 Kbytes or 3600 seconds
2021-06-19 10:46:33.223 IPsec ESP Session (IPsec SA) 9 (Client: 15760) (192.168.0.1:4500 -> 0.0.0.0:4500): A new IPsec SA (Direction: Server -> Client) is created. SPI: 0xCAE24C36, DH Group: (null), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 250000 Kbytes or 3600 seconds
2021-06-19 10:46:33.223 IPsec ESP Session (IPsec SA) 9 (Client: 15760) (192.168.0.1:4500 -> 0.0.0.0:4500): This IPsec SA is established between the server and the client.
2021-06-19 10:46:33.223 IPsec Client 15760 (192.168.0.1:4500 -> 0.0.0.0:4500): The L2TP Server Module is started.
2021-06-19 10:46:33.253 L2TP PPP Session [192.168.0.1:1701]: A new PPP session (Upper protocol: L2TP) is started. IP Address of PPP Client: 192.168.0.1 (Hostname: "ClientPC"), Port Number of PPP Client: 1701, IP Address of PPP Server: 0.0.0.0, Port Number of PPP Server: 1701, Client Software Name: "L2TP VPN Client - Microsoft", IPv4 TCP MSS (Max Segment Size): 1314 bytes
2021-06-19 10:46:33.556 On the TCP Listener (Port 0), a Client (IP address 192.168.0.1, Host name "192.168.0.1", Port number 1701) has connected.
2021-06-19 10:46:33.556 For the client (IP address: 192.168.0.1, host name: "192.168.0.1", port number: 1701), connection "CID-37" has been created.
2021-06-19 10:46:33.556 SSL communication for connection "CID-37" has been started. The encryption algorithm name is "(null)".
2021-06-19 10:46:33.566 [HUB "HOME"] The connection "CID-37" (IP address: 192.168.0.1, Host name: 192.168.0.1, Port number: 1701, Client name: "L2TP VPN Client - Microsoft", Version: 5.01, Build: 9674) is attempting to connect to the Virtual Hub. The auth type provided is "External server authentication" and the user name is "VpnUser".
2021-06-19 10:46:33.566 [HUB "HOME"] Connection "CID-37": Successfully authenticated as user "VpnUser".
2021-06-19 10:46:33.566 [HUB "HOME"] Connection "CID-37": The new session "SID-VPNUSER-[L2TP]-12" has been created. (IP address: 192.168.0.1, Port number: 1701, Physical underlying protocol: "Legacy VPN - L2TP")
2021-06-19 10:46:33.566 [HUB "HOME"] Session "SID-VPNUSER-[L2TP]-12": The parameter has been set. Max number of TCP connections: 1, Use of encryption: Yes, Use of compression: No, Use of Half duplex communication: No, Timeout: 20 seconds.
2021-06-19 10:46:33.566 [HUB "HOME"] Session "SID-VPNUSER-[L2TP]-12": VPN Client details: (Client product name: "L2TP VPN Client - Microsoft", Client version: 501, Client build number: 9674, Server product name: "SoftEther VPN Server Developer Edition (64 bit) (Open Source)", Server version: 501, Server build number: 9674, Client OS name: "L2TP VPN Client - Microsoft", Client OS version: "-", Client product ID: "-", Client host name: "ClientPC", Client IP address: "192.168.0.1", Client port number: 1701, Server host name: "0.0.0.0", Server IP address: "0.0.0.0", Server port number: 1701, Proxy host name: "", Proxy IP address: "0.0.0.0", Proxy port number: 0, Virtual Hub name: "HOME", Client unique ID: "3418<<Redacted>>8B345")
2021-06-19 10:46:33.576 IPsec ESP Session (IPsec SA) 9 (Client: 15760) (192.168.0.1:4500 -> 0.0.0.0:4500): This IPsec SA is deleted.
2021-06-19 10:46:33.616 IPsec IKE Session (IKE SA) 8 (Client: 15760) (192.168.0.1:4500 -> 0.0.0.0:4500): This IKE SA is deleted.
2021-06-19 10:46:33.616 IPsec ESP Session (IPsec SA) 9 (Client: 15760) (192.168.0.1:4500 -> 0.0.0.0:4500): This IPsec SA is deleted.
2021-06-19 10:46:33.778 L2TP PPP Session [192.168.0.1:1701]: The PPP session is disconnected because the upper-layer protocol "L2TP" has been disconnected.
2021-06-19 10:46:33.778 L2TP PPP Session [192.168.0.1:1701]: The PPP session is disconnected.
2021-06-19 10:46:33.878 [HUB "HOME"] Session "SID-VPNUSER-[L2TP]-12": The session has been terminated. The statistical information is as follows: Total outgoing data size: 0 bytes, Total incoming data size: 0 bytes.
2021-06-19 10:46:33.909 Connection "CID-37" terminated by the cause "The VPN session has been deleted. It is possible that either the administrator disconnected the session or the connection from the client to the VPN Server has been disconnected." (code 11).
2021-06-19 10:46:33.909 Connection "CID-37" has been terminated.
2021-06-19 10:46:33.909 The connection with the client (IP address 192.168.0.1, Port number 1701) has been disconnected.
2021-06-19 10:46:44.018 IPsec Client 15760 (192.168.0.1:4500 -> 0.0.0.0:4500): This IPsec Client is deleted.
Does anyone have any solution to this problem?

Post Reply