NEC IX2105 <-> SoftetherのVPNが1時間ごとに切れたり復活する事象

[yaizawa]

お世話になります。
NEC IX2105を使ってSoftetherにEtherIP接続でVPNを設定いたしましたが、なぜか1時間ごとにセッションが繋がったり切れたりする事象が起きております。
恐らく何かしらの設定が誤っていて事象が起きていると思われますが、お知恵を拝借いただけますでしょうか。


<環境>
Server: Softether VPN Server (64 bit) Version 4.44 Build 9807 on Linux
Client: NEC Univerge IX2105 Version 10.2.42

<Softether側のログ (関係部分のみ抜粋、IPアドレスマスク済み)>
※ 10:28～11:27は疎通可、11:27～12:26は疎通不可、12:27～13:25は疎通可
2026-01-01 10:28:23.701 IPsec Client 2169 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec client is created.
2026-01-01 10:28:23.701 IPsec IKE Session (IKE SA) 1535 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IKE SA (Aggressive Mode) is created. Initiator Cookie: 0x37CE5CCC2E52909B, Responder Cookie: 0x55F6E234B8A4B78B, DH Group: MODP 1024 (Group 2), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 10:28:23.711 IPsec Client 2169 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500):
2026-01-01 10:28:23.731 IPsec IKE Session (IKE SA) 1535 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IKE SA is established between the server and the client.
2026-01-01 10:28:23.731 IPsec IKE Session (IKE SA) 1535 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): The client initiates a QuickMode negotiation.
2026-01-01 10:28:23.731 IPsec ESP Session (IPsec SA) 1506 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec SA (Direction: Client -> Server) is created. SPI: 0x2131FAF6, DH Group: (null), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 10:28:23.731 IPsec ESP Session (IPsec SA) 1506 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec SA (Direction: Server -> Client) is created. SPI: 0x1297F585, DH Group: (null), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 10:28:23.751 IPsec ESP Session (IPsec SA) 1506 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec SA is established between the server and the client.
2026-01-01 10:28:26.668 EtherIP / L2TPv3 Session 730 (2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500 -> 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500): The EtherIP / L2TPv3 Module is started.
2026-01-01 10:28:26.668 IPsec Client 2169 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500):
2026-01-01 10:28:26.718 EtherIP / L2TPv3 Session 730 (2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500 -> 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500): The internal pipe was created between the EtherIP / L2TPv3 module to the Virtual Hub "VPN". The using username is "ix01". The IPv4 TCP MSS (Max Segment Size) to be set is 1258 bytes.
2026-01-01 10:28:26.718 On the TCP Listener (Port 0), a Client (IP address 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Host name "2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe", Port number 500) has connected.
2026-01-01 10:28:26.718 For the client (IP address: 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, host name: "2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe", port number: 500), connection "CID-4598" has been created.
2026-01-01 10:28:26.718 SSL communication for connection "CID-4598" has been started. The encryption algorithm name is "(null)".
2026-01-01 10:28:26.718 [HUB "VPN"] The connection "CID-4598" (IP address: 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Host name: 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Port number: 500, Client name: "EtherIP Client", Version: 4.44, Build: 9807) is attempting to connect to the Virtual Hub. The auth type provided is "External server authentication" and the user name is "ix01".
2026-01-01 10:28:26.718 [HUB "VPN"] Connection "CID-4598": Successfully authenticated as user "ix01".
2026-01-01 10:28:26.718 [HUB "VPN"] Connection "CID-4598": The new session "SID-IX01-[ETHERIP]-731" has been created. (IP address: 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Port number: 500, Physical underlying protocol: "Legacy VPN - ETHERIP")
2026-01-01 10:28:26.718 [HUB "VPN"] Session "SID-IX01-[ETHERIP]-731": 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.
2026-01-01 10:28:26.718 [HUB "VPN"] Session "SID-IX01-[ETHERIP]-731": VPN Client details: (Client product name: "EtherIP Client", Client version: 444, Client build number: 9807, Server product name: "SoftEther VPN Server (64 bit)", Server version: 444, Server build number: 9807, Client OS name: "EtherIP Client", Client OS version: "-", Client product ID: "-", Client host name: "", Client IP address: "2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe", Client port number: 500, Server host name: "2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239", Server IP address: "2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239", Server port number: 500, Proxy host name: "", Proxy IP address: "0.0.0.0", Proxy port number: 0, Virtual Hub name: "VPN", Client unique ID: "7753D03A7454A1DE9B5D5F3D36126487")
2026-01-01 10:28:26.718 EtherIP / L2TPv3 Session 730 (2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500 -> 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500): The connection from the EtherIP / L2TPv3 module to the Virtual Hub "VPN" succeeded.
2026-01-01 11:27:23.797 IPsec IKE Session (IKE SA) 1535 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): The client initiates a QuickMode negotiation.
2026-01-01 11:27:23.797 IPsec ESP Session (IPsec SA) 1508 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec SA (Direction: Client -> Server) is created. SPI: 0x7545D35B, DH Group: (null), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 11:27:23.797 IPsec ESP Session (IPsec SA) 1508 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec SA (Direction: Server -> Client) is created. SPI: 0x4E747E8F, DH Group: (null), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 11:27:23.818 IPsec ESP Session (IPsec SA) 1508 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec SA is established between the server and the client.
2026-01-01 11:27:53.764 IPsec Client 2172 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec client is created.
2026-01-01 11:27:53.774 IPsec IKE Session (IKE SA) 1537 (Client: 2172) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IKE SA (Aggressive Mode) is created. Initiator Cookie: 0xB9A15052A8783FE9, Responder Cookie: 0x9F813511F6B83DB9, DH Group: MODP 1024 (Group 2), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 11:27:53.774 IPsec Client 2172 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500):
2026-01-01 11:27:53.794 IPsec IKE Session (IKE SA) 1537 (Client: 2172) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IKE SA is established between the server and the client.
2026-01-01 11:28:03.812 IPsec Client 2172 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec Client is deleted.
2026-01-01 11:28:03.812 IPsec IKE Session (IKE SA) 1537 (Client: 2172) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IKE SA is deleted.
2026-01-01 11:28:03.833 IPsec Client 2173 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec client is created.
2026-01-01 11:28:13.938 IPsec Client 2173 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec Client is deleted.
2026-01-01 11:28:24.767 IPsec IKE Session (IKE SA) 1535 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IKE SA is deleted.
2026-01-01 11:28:24.767 IPsec ESP Session (IPsec SA) 1506 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec SA is deleted.
2026-01-01 11:28:24.767 IPsec ESP Session (IPsec SA) 1508 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec SA is deleted.
2026-01-01 11:28:24.767 IPsec ESP Session (IPsec SA) 1506 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec SA is deleted.
2026-01-01 11:28:24.767 IPsec ESP Session (IPsec SA) 1508 (Client: 2169) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec SA is deleted.
2026-01-01 11:28:34.939 IPsec Client 2169 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec Client is deleted.
2026-01-01 11:28:34.939 EtherIP / L2TPv3 Session 730 (2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500 -> 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500): The EtherIP / L2TPv3 Module is stopped.
2026-01-01 11:28:34.939 [HUB "VPN"] Session "SID-IX01-[ETHERIP]-731": The session has been terminated. The statistical information is as follows: Total outgoing data size: 1987083 bytes, Total incoming data size: 2903690 bytes.
2026-01-01 11:28:34.970 Connection "CID-4598" 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).
2026-01-01 11:28:34.970 Connection "CID-4598" has been terminated.
2026-01-01 11:28:34.970 The connection with the client (IP address 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Port number 500) has been disconnected.
2026-01-01 12:26:23.867 IPsec Client 2175 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec client is created.
2026-01-01 12:26:23.867 IPsec IKE Session (IKE SA) 1539 (Client: 2175) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IKE SA (Aggressive Mode) is created. Initiator Cookie: 0xF39668722B40DFCC, Responder Cookie: 0x748B49E755520973, DH Group: MODP 1024 (Group 2), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 12:26:23.867 IPsec Client 2175 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500):
2026-01-01 12:26:23.887 IPsec IKE Session (IKE SA) 1539 (Client: 2175) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IKE SA is established between the server and the client.
2026-01-01 12:26:23.887 IPsec IKE Session (IKE SA) 1539 (Client: 2175) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): The client initiates a QuickMode negotiation.
2026-01-01 12:26:23.887 IPsec ESP Session (IPsec SA) 1510 (Client: 2175) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec SA (Direction: Client -> Server) is created. SPI: 0x7EAC37A6, DH Group: (null), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 12:26:23.887 IPsec ESP Session (IPsec SA) 1510 (Client: 2175) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): A new IPsec SA (Direction: Server -> Client) is created. SPI: 0x56425358, DH Group: (null), Hash Algorithm: SHA-1, Cipher Algorithm: AES-CBC, Cipher Key Size: 128 bits, Lifetime: 4294967295 Kbytes or 3600 seconds
2026-01-01 12:26:23.908 IPsec ESP Session (IPsec SA) 1510 (Client: 2175) (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500): This IPsec SA is established between the server and the client.
2026-01-01 12:26:24.725 EtherIP / L2TPv3 Session 732 (2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500 -> 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500): The EtherIP / L2TPv3 Module is started.
2026-01-01 12:26:24.725 IPsec Client 2175 (2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500 -> 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500):
2026-01-01 12:26:24.765 EtherIP / L2TPv3 Session 732 (2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500 -> 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500): The internal pipe was created between the EtherIP / L2TPv3 module to the Virtual Hub "VPN". The using username is "ix01". The IPv4 TCP MSS (Max Segment Size) to be set is 1258 bytes.
2026-01-01 12:26:24.765 On the TCP Listener (Port 0), a Client (IP address 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Host name "2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe", Port number 500) has connected.
2026-01-01 12:26:24.765 For the client (IP address: 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, host name: "2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe", port number: 500), connection "CID-4606" has been created.
2026-01-01 12:26:24.765 SSL communication for connection "CID-4606" has been started. The encryption algorithm name is "(null)".
2026-01-01 12:26:24.765 [HUB "VPN"] The connection "CID-4606" (IP address: 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Host name: 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Port number: 500, Client name: "EtherIP Client", Version: 4.44, Build: 9807) is attempting to connect to the Virtual Hub. The auth type provided is "External server authentication" and the user name is "ix01".
2026-01-01 12:26:24.765 [HUB "VPN"] Connection "CID-4606": Successfully authenticated as user "ix01".
2026-01-01 12:26:24.765 [HUB "VPN"] Connection "CID-4606": The new session "SID-IX01-[ETHERIP]-733" has been created. (IP address: 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe, Port number: 500, Physical underlying protocol: "Legacy VPN - ETHERIP")
2026-01-01 12:26:24.765 [HUB "VPN"] Session "SID-IX01-[ETHERIP]-733": 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.
2026-01-01 12:26:24.765 [HUB "VPN"] Session "SID-IX01-[ETHERIP]-733": VPN Client details: (Client product name: "EtherIP Client", Client version: 444, Client build number: 9807, Server product name: "SoftEther VPN Server (64 bit)", Server version: 444, Server build number: 9807, Client OS name: "EtherIP Client", Client OS version: "-", Client product ID: "-", Client host name: "", Client IP address: "2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe", Client port number: 500, Server host name: "2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239", Server IP address: "2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239", Server port number: 500, Proxy host name: "", Proxy IP address: "0.0.0.0", Proxy port number: 0, Virtual Hub name: "VPN", Client unique ID: "7753D03A7454A1DE9B5D5F3D36126487")
2026-01-01 12:26:24.765 EtherIP / L2TPv3 Session 732 (2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239:500 -> 2404:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:fffe:500): The connection from the EtherIP / L2TPv3 module to the Virtual Hub "VPN" succeeded.

<IX2105側のログ (該当部分抜粋、IPアドレスマスク済み)>
2026/01/01 10:28:23 IKE.001: Begin IKE phase 1 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 10:28:23 IKE.047: Initiator negotiation using Aggressive mode
2026/01/01 10:28:23 IKE.002: Finish IKE phase 1 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 10:28:23 IKE.001: Begin IKE phase 2 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 10:28:23 KEY.031: Create inbound SA[ESP], SPI 0x1297f585, Tunnel(if Tunnel1.0)
2026/01/01 10:28:23 KEY.033: Update outbound SA[ESP], SPI 0x2131faf6, Tunnel(if Tunnel1.0)
2026/01/01 10:28:23 IKE.002: Finish IKE phase 2 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 10:29:23 IKE.012: Send delete information, protocol ESP, SPI 0xf220bc7e
2026/01/01 10:29:23 KEY.032: Delete inbound SA[ESP], SPI 0xf220bc7e, Tunnel(if Tunnel1.0)
2026/01/01 11:27:23 IKE.001: Begin IKE phase 2 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 11:27:23 KEY.031: Create inbound SA[ESP], SPI 0x4e747e8f, Tunnel(if Tunnel1.0)
2026/01/01 11:27:23 KEY.033: Update outbound SA[ESP], SPI 0x7545d35b, Tunnel(if Tunnel1.0)
2026/01/01 11:27:23 IKE.002: Finish IKE phase 2 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 11:27:53 IKE.001: Begin IKE phase 1 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 11:27:53 IKE.047: Initiator negotiation using Aggressive mode
2026/01/01 11:27:53 IKE.002: Finish IKE phase 1 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 11:28:03 IKE.013: Receive delete information from 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239, protocol ISAKMP
2026/01/01 11:28:03 IKE.003: Delete phase 1 negotiation table, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 11:28:23 KEY.032: Delete inbound SA[ESP], SPI 0x1297f585, Tunnel(if Tunnel1.0)
2026/01/01 11:28:24 IKE.004: IKE-SA lifetime expired, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 11:28:24 IKE.011: Send delete information to 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239, protocol ISAKMP
2026/01/01 11:28:24 IKE.003: Delete phase 1 negotiation table, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 12:26:23 IKE.001: Begin IKE phase 1 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 12:26:23 IKE.047: Initiator negotiation using Aggressive mode
2026/01/01 12:26:23 IKE.002: Finish IKE phase 1 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 12:26:23 IKE.001: Begin IKE phase 2 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 12:26:23 KEY.031: Create inbound SA[ESP], SPI 0x56425358, Tunnel(if Tunnel1.0)
2026/01/01 12:26:23 KEY.033: Update outbound SA[ESP], SPI 0x7eac37a6, Tunnel(if Tunnel1.0)
2026/01/01 12:26:23 IKE.002: Finish IKE phase 2 negotiation, destination 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239
2026/01/01 12:27:23 IKE.012: Send delete information, protocol ESP, SPI 0x4e747e8f
2026/01/01 12:27:23 KEY.032: Delete inbound SA[ESP], SPI 0x4e747e8f, Tunnel(if Tunnel1.0)

<IX2105のconfigのうちVPN関係部分抜粋>
(前略)
ike proposal ike-prop2 encryption aes hash sha group 1024-bit lifetime 3600
!
ike policy ike-policy2 peer 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239 key vpn mode aggressive ike-prop2
ike keepalive ike-policy2 10 2
ike local-id ike-policy2 keyid ix01
ike nat-traversal policy ike-policy2 keepalive 10
ike rekey remaining-lifetime policy ike-policy2 second 30
!
ipsec autokey-proposal ipsec-prop2 esp-aes esp-sha lifetime time 3600
!
ipsec autokey-map ipsec-static-map2 permit-list peer 2401:YYYY:YYYY:YYYY:YYYY:YYYY:YYYY:239 ipsec-prop2
!
(中略)
interface Tunnel1.0
description Softether
tunnel mode ether-ip ipsec
no ip address
ip tcp adjust-mss auto
ip filter flt-list0 1 in
ipsec policy tunnel ipsec-static-map2 out
bridge-group 1
ip ospf mtu-ignore
no shutdown
!
(後略)

<お知恵を借りたいこと>
・事象の原因と思われる設定箇所 (Softether側、IX2105側ともに)
・事象を特定するのに足りない情報があるのであれば、どのような情報が不足しているか

すみませんが、どうぞよろしくお願いいたします。