How do I connect to MySQL when it's setting behind 2 layers of ssh?

Question

I have a MySQL server sitting behind a bastion server that I wish to connect to from my local machine.

Ideally I want to port-forward the MySQL port (3316 in this case) to a local port on my machine.

I've tried plink -ssh -L 3306:my.sql.ip.address:3316 my.bastion.server ,but this is not working.

I've got one ssh login for the bastion server and another login for the machine mysql server is running on.

Answer 1

You can double-chain SSH port forwards, bit a slightly easier method is to set up a "proxy" config in .ssh/config:

Host *%proxy
    ProxyCommand ssh proxy-user@proxy.host "nc -w1 $(echo %h | cut -d%% -f1) 22"
    ForwardAgent yes
    StrictHostKeyChecking no

Then use ssh -L 3306:127.0.0.1:3316 final-user@final.host%proxy to bring up the seesion.

I use this all the time, although normally with dyanamic port forwards (-D 1080) to get to management modules of hosts behind overly restrictive firewalls.