For example: you may get vtund client-server daemon errors like these !
You can kindly watch my video above and learn how you can debug, avoid and address the same.
vtund :: Client Side error:
root@xubuntu-desktop:/etc# vtund -f /etc/vtund-client.conf my_tunnel 192.168.0.88 -n
vtund[2054]: VTun client ver 3.X 02/05/2018 started
vtund[2054]: Connecting to 192.168.0.88
vtund[2054]: Use SSL-aware challenge/response
vtund[2054]: Remote Server sends <TuK>
.
vtund[2054]: Session my_tunnel[192.168.0.88] opened
vtund[2054]: Input/output error (5)
SIOCDELRT: No such process
vtund[2054]: Session my_tunnel[192.168.0.88] closed
vtund[2054]: Exit
root@xubuntu-desktop:/etc# vtund :: Server Side error:
root@1TBWDBlueMobile:/etc# vtund -f /etc/vtund-vm-setup-server.conf -s -n
vtund[11981]: VTUN server ver 3.X 02/05/2018 (standalone)
vtund[12213]: Use SSL-aware challenge/response
vtund[12213]: Session my_tunnel[192.168.0.88:44936] opened
vtund[12213]: Connection closed by other side
SIOCADDRT: Network is down
SIOCDELRT: No such process
vtund[12213]: Session my_tunnel closed
vtund[11981]: Terminated
root@1TBWDBlueMobile:/etc#