autossh | Persistent SSH tunnels | Proxy library

Your Docker DNS could be breaking index file resolution. Try using docker build --network=host

The solution I found was opening 3 terminal and running that 3 things respectively.

I create a bash file main.sh which contained:

I have been struggling with this for awhile too. My answer was probably pretty basic and a typical beginner mistake, and may not be your answer, but I will post this here just in case someone else is having trouble and this helps them:

The public key of the machine you are trying to reverse ssh from to needs to exist on the authorized_keys file on your local machine.

Reverse SSH connects to a local port, which is in reality your own local machine, so it will be looking for a public key on your local machines authorized_keys file that does not exist. It is easy to get confused with this because you are using "localhost" as the address, but just imagine it that you are opening a portal into a remote location at some random port, and then acting as that remote user to connect from that location to the port you made. When it connects to the port, it will still need ask for permission through the port to send commands down. Since it is a portal into your home, it will look there for the key. If there is no key at the other end of the port, it wont work.

ELI5 style:

You want another world to send you stuff but they can't because you are in a secret location, so you make a red port and a blue port into the other world.

You jump through red port, but the people at the other end don't know where blue port is, so you have to tell them where the blue port is. They attempt to go through the port but cant get in because you have not yet authorized them to come over and security isn't having it today.

So you have them make a key card there and you bring it back to your own world and tell your own security "this key card is good, let them in".

Now you can go back over again, and tell them to knock. This time the security sees that these are friends and they get let in.

So:

Here is the two commands that allow you to use autossh:

After digging around, I figured it out. My host, example.com, points to a load balancer with a bunch of listener rules. I made it so that if path=/mychatapp/*, then forward to the ec2 instance running the app. This is fine, but socket.io was making calls with host=example.com so it was hitting example.com/socket.io/etcetcetc... I added another load balancer listener rule if path=/socket.io/*, then also forward it to the ec2 instance. This works out.

This solution is pretty hacky since it means I couldn't run a second socket.io app. A better answer would be to somehow change the default call from "/socket.io" to "/mychatapp/socket.io" so that I wouldn't require another listener rule. I tried a few ways to do this, but it didn't work. Since this is a small project, I will stick with this solution.

Replace ~/.ssh/etherwan.key in your rc.d script with /home/ron/.ssh/etherwan.key

The '~' character is expanded to the user's home directory by the shell, but rc.d scripts are run as root.

Instead of After=network.target, use After=network-online.target.

More about systemd network targets are documented on the systemd wiki page.