How to expose your local server to the Internet

I occasionally have the need to temporarily expose my local development server to the Internet. I say temporarily since you should never expose your development server to the Internet unless it’s absolutely required and even then it should be only temporarily. This article should save me (and hopefully someone else) some time the next time I need to expose my local server to the Internet.

Your local development server could be anything but let’s pretend that we are developing a Ruby on Rails application and we want to demo the application to someone who is out of the office. Assuming that you are behind a firewall your best option is to route the traffic through a remote server that has a public ip address. There is an alternative but it’s less reliable.

Below are the steps that you need to take in order to expose your rails application to the Internet. I will assume that the remote server has a public dns entry “remote.company.com”.

  • Setup your remote server to allow tcp forwarding
  • Create an ssh tunnel between you and the remote server

It really is simple as that. Let’s get to work.

Setup your remote server to allow tcp forwarding

Connect to your server and execute the following commands:

sudo echo "AllowTcpForwarding yes" >> /etc/ssh/sshd_config
sudo echo "GatewayPorts yes" >> /etc/ssh/sshd_config 
sudo service ssh restart

Please note that you should check if these options are already set in the sshd configuration to avoid duplicate entries.

You are all done and you can move to the next step. For the curious ones, here’s what you did. AllowTcpForwarding is self-explanatory—it enables tcp forwarding. Without this we wouldn’t be able to forward any ports. GatewayPorts enables remote hosts to connect to the forwarded ports. If we didn’t specify this no one would be able to connect to the forwarded port on our remote server.

Create an ssh tunnel between you and the remote server

This step is even easier, just run the following command:

ssh -R0.0.0.0:7000:localhost:3000 user@remote.company.com

The above command will tunnel all traffic between remote.company.com:7000 and localhost:3000. Now everyone on Internet can access your local development server at remote.company.com:7000 (assuming that remote.company.com is accessible from the Internet).

Alternative

I’ve mentioned that there is an alternative if you don’t have a public facing remote server. I’ve briefly used localtunnel which when executed returns you a link which you can send to anyone who needs to connect to your local server.

However I had some issues with the service since it was very unstable when I used it. With that said I didn’t use it for more than an hour or two so it might have been a temporary hickup.

There’s also a new, beta version of localtunnel.

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