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I try to maintain my mother's PC remotely and as part of that sometime back enabled the SSH server so I could tunnel RDP over that. Now it's been working fine for sometime 2 years+. Just recently it drops after not more than 3 minutes sometimes way less.

I've checked the keep alive is set on the clients which work fine to other servers and now enabled keep alive too on the server. Had a batch file running which intermittently pinged the router and it still drops so I am pretty certain the link is not idle. This is accessing remotely, trying to track this down I installed an OpenVPN server on the machine and OpenWRT on the router. In all 3 cases the behaviour is the same but the VPN connections are solid. Note RDP crashes with the same regularity as SSH and at the sometime as far as I can determine. I think RDP like SSH is TCP which may be a clue.

Turned on debug on the server which gives

5952 2022-05-16 22:55:21.056 debug2: channel 0: request keepalive@openssh.com confirm 1
5952 2022-05-16 22:55:21.056 debug3: send packet: type 98
5952 2022-05-16 22:55:21.087 debug3: receive packet: type 100
5952 2022-05-16 22:55:21.087 debug1: Got 100/17 for keepalive
5952 2022-05-16 22:55:51.059 debug2: channel 0: request keepalive@openssh.com confirm 1
5952 2022-05-16 22:55:51.059 debug3: send packet: type 98
5952 2022-05-16 22:55:51.090 debug3: receive packet: type 100
5952 2022-05-16 22:55:51.090 debug1: Got 100/18 for keepalive
5952 2022-05-16 22:56:04.936 debug3: recv - from CB ERROR:10053, io:00000275D9B24550
5952 2022-05-16 22:56:04.936 Read error from remote host 192.168.7.2 port 52765: Connection aborted
5952 2022-05-16 22:56:04.936 debug1: do_cleanup
12868 2022-05-16 22:56:04.967 debug3: mm_request_receive entering
12868 2022-05-16 22:56:04.967 debug1: do_cleanup

As best as I can determine CB ERROR:10053 is reset by software. I've tried with the firewall off and with defender disabled and the behaviour is exactly the same. Given I've now got VPN I could live without SSH if RDP were not affected too.

Any idea what to try next? I can probably get there in person next week for a day or so before I go away again for some months so it would be nice to resolve so I can keep her online if there's any issues.

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1 Answers1

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In case it helps someone else.

Finally managed to get to the PC and examine the event logs where every 3 minutes was this little gem.

The IP address lease 192.168.17.10 for the Network Card with network address 0xD850E64AB4CE has been denied by the DHCP server 192.168.17.1 (The DHCP Server sent a DHCPNACK message

The PC was set with the IP address fixed by a permanent lease in the router. Making a fixed address in the network card, i.e turning off DHCP has resolved it albeit I'd consider this a workaround rather than a resolution.

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