I'm trying to create a SSH tunnel between 2 Raspberry PI's both running Debian Bookworm.
I try to establish the connection using the command
sudo ssh -w0:0 <user>@<ip> -p<ssh port> true
But it fails with
...
debug1: Requesting tun unit 0 in mode 1
debug1: sys_tun_open: failed to configure tunnel (mode 1): Invalid argument
Tunnel device open failed.
Could not request tunnel forwarding.
debug1: channel 0: new session [client-session] (inactive timeout: 0)
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug3: send packet: type 90
debug1: Requesting [email protected]
debug3: send packet: type 80
debug1: Entering interactive session.
...
I've changed the below config files
/etc/ssh/sshd_config
AllowTcpForwarding yes
PermitTunnel yes
/etc/ssh/ssh_config
Tunnel point-to-point
/etc/sysctl.conf
net.ipv4.ip_forward = 1
The tun0 interface is created on both devices using sudo nmtui
tun0: flags=209<UP,POINTOPOINT,RUNNING,NOARP> mtu 1480
inet <local ip> netmask 255.255.255.252 destination <remote ip>
tunnel txqueuelen 1000 (IPIP Tunnel)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Can anybody help me getting this error fixed?