what?
ssh reverse tunnel in ~100 lines of code.
- no autossh, no systemd-restarts, and no ssh alive-interval configurations
how?
- manually checking ssh tunnel connection correctness every 30 seconds by running 'hostname' on target comp and comparing it with config line.
why?
- because internet examples show's sstemd+autossh+aliveinterval combinations
- all 3 of them try to 'check if ssh works, and kill it/restart it'
- alive-interval config are complex, there are server and client side and involves time to test it well.
- autossh needs aditional monitoring port, or it is useless
- result is that in 1% of situations, reverse tunnel do not works, especialy when wifi is involved, leaving user in helpless and hard to debug situations. Also, someties there was server-side part alive, and client-side killed, which disables future forwarding attemps. Tcp connection is in that situation in TIME_WAIT state, and idealy, there should be some part of client that connects to server and kill's all before next attempts.
- so, for 98% situations, simple
ssh -o ExitOnForwardFailure=yes -R remoteip:tunnelport:localip:localport user@remoteipserverinside some endless loop, works well. - for 99% situations there is autossh and keep-alive system (still one or few lines of code)
revloopis trying to solve that last 1% situations, by maybe too big effort (~100 lines code). By doing loop, manually checking if it is ok all way to the end, and killing both sides when needed.- it also tries to make installation process simpler, instead of remembering all client and server ssh-cfg options, Makefile indicates known initial problems that usually tooks too much time when correcting them over and over again on different computers.
installation?
git clone https://github.com/asainnp/revtunnel ; cd revtunnel`
cp config.sh.example config.sh ; vim config.sh # edit ports and addresses
make # complete check of configuration and connection
sudo make install # installing files to /opt/revtunnel and service