I try to set up an ssh vpn (Debian OS server and client both).
I changed /etc/ssh/sshd_config (the server):
PermitTunnel yes PermitRootLogin without-password
but when I try to connect (the client):
$ ssh -NTCf -vvvw 0:0 root@server-ip ... debug1: Authentication succeeded (publickey). Authenticated to <server-ip> ([<server-ip>]:22). debug1: Requesting tun unit 0 in mode 1 debug1: sys_tun_open: failed to configure tunnel (mode 1): Operation not permitted Tunnel device open failed. Could not request tunnel forwarding. ...
What can be wrong? Please help!
I tried to run ssh as root, but still has errors (the client):
# ssh -i ~user/.ssh/id_rsa -NTCf -vvvw any root@server-ip .... debug1: Requesting tun unit 2147483647 in mode 1 debug1: sys_tun_open: tunnel mode 1 fd 5 Tunnel device open failed. Could not request tunnel forwarding. debug2: fd 3 setting TCP_NODELAY ...
OpenSSH_7.7p1 Debian-2, OpenSSL 1.0.2o 27 Mar 2018 Linux 4.16.0-2-amd64 #1 SMP Debian 4.16.12-1 (2018-05-27) x86_64 Debian GNU/Linux testing (buster)