>_
Expose local servers to the internet
No installation, no signup
ssh -R 80:localhost:3000 serveo.net
Try it! Copy and paste this into your terminal.

How does it work?

Serveo is an SSH server just for remote port forwarding. When a user connects to Serveo, they get a public URL that anybody can use to connect to their localhost server.

Manual

Basic use

ssh -R 80:localhost:3000 serveo.net

The -R option instructs your SSH client to request port forwarding from the server and proxy requests to the specified host and port (usually localhost). A subdomain of serveo.net will be assigned to forward HTTP traffic.

Request multiple tunnels at once

ssh -R 80:localhost:8888 -R 80:localhost:9999 serveo.net

The target server doesn't have to be on localhost

 ssh -R 80:example.com:80 serveo.net

Request a particular subdomain

The subdomain is chosen deterministically based on your IP address, the provided SSH username, and subdomain availability, so you'll often get the same subdomain between restarts. You can also request a particular subdomain:

ssh -R incubo:80:localhost:8888 serveo.net
ssh -R incubo.serveo.net:80:localhost:8888 serveo.net

Change the SSH username to get assigned a different subdomain:

ssh -R 80:localhost:8888 foo@serveo.net
ssh -R 80:localhost:8888 -l foo serveo.net

SSH forwarding

Request forwarding for port 22, and serveo.net will act as a jump host, allowing you to conveniently SSH into your machine (a unique alias is required):

ssh -R myalias:22:localhost:22 serveo.net

Then you can establish an SSH connection using serveo.net as an intermediary like this:

ssh -J serveo.net user@myalias

The -J option was introduced in the OpenSSH client version 7.3. If you have an older client, you can use the ProxyCommand option instead:

ssh -o ProxyCommand="ssh -W myalias:22 serveo.net" user@myalias

Generic TCP forwarding

If you request a port other than 80, 443, or 22, raw TCP traffic will be forwarded. (In this case, there's no way to route connections based on hostname, and the host, if specifed, will be ignored.)

ssh -R 1492:localhost:1492 serveo.net

If port 0 is requested, a random TCP port will be forwarded:

ssh -R 0:localhost:1492 serveo.net

Connect on port 443

In some environments, outbound port 22 connections are blocked. For this reason, you can also connect on port 443.

ssh -p 443 -R 80:localhost:8888 serveo.net

Keep the connection alive

Use ServerAliveInterval to prevent an idle connection from timing out:

ssh -o ServerAliveInterval=60 -R 80:localhost:8888 serveo.net

Automatically reconnect

Use autossh for more persistent tunnels. Use "-M 0" to disable autossh's connectivity checking (rely on ServerAliveInterval and ServerAliveCountMax instead):

autossh -M 0 -R 80:localhost:8888 serveo.net

See https://www.everythingcli.org/ssh-tunnelling-for-fun-and-profit-autossh/ for more about autossh.

GUI

Pressing g will start a GUI session. Use up and down arrow keys to inspect requests/responses, and left and right arrow keys to switch between request and response views. Use j, k, u, d, p, and n to scroll the lower inspector pane. Press r to replay the selected request. Press h or ? at any time for help.

Custom Domain

To use your own domain or subdomain, you'll first need an SSH key pair. Use the ssh-keygen program to generate a key pair if you don't already have one.

Next, use ssh-keygen -l and note your key's fingerprint. Here's an example output:

2048 SHA256:pmc7ZRv7ymCmghUwHoJWEm5ToSTd33ryeDeps5RnfRY no comment (RSA)

In this example, the fingerprint is SHA256:pmc7ZRv7ymCmghUwHoJWEm5ToSTd33ryeDeps5RnfRY.

Now you need to add two DNS records for the domain or subdomain you'd like to use:

  1. An A record pointing to 159.89.214.31.
  2. For each SSH key to allow, a TXT record in the form of authkeyfp=[fingerprint]. For the example key above, the DNS record would be authkeyfp=SHA256:pmc7ZRv7ymCmghUwHoJWEm5ToSTd33ryeDeps5RnfRY.

Once your DNS records are in place, you can request your subdomain/domain from Serveo:

ssh -R subdomain.example.com:80:localhost:3000 serveo.net

When you request port forwarding for subdomain.example.com, Serveo will fetch the TXT records from your DNS server and only allow forwarding if you've provided a public key with the same fingerprint as specified in TXT records.

Alternatives

ngrok

Serveo is an excellent alternative to ngrok. Serveo was inspired by ngrok and attempts to serve many of the same purposes. The primary advantage of Serveo over ngrok is the use of your existing SSH client, so there's no client application to install.

Other slight advantages include preservation of URLs across reconnect for free (ngrok allows this only for paid accounts) and in-terminal request inspection and replay (ngrok uses a web interface).

OpenSSH Server

Using Serveo instead of OpenSSH frees you from having to configure and maintain a server. It also handles HTTPS and subdomain generation, two features that complicate a typical SSH port-forwarding setup.

If Serveo doesn't meet your needs, this guide has some ideas for setting up OpenSSH.

Host it yourself

This free version is intended for evaluative and personal use and allows no more than 3 total simultaneous tunnels per instance.

Email me at trevor@serveo.net if you're interested in licensing Serveo for business use or otherwise need more than 3 tunnels at a time.

Download

Linux

Mac

Windows

Use

The server's behavior is configured using command line arguments. Use -h to see all options.

./serveo -h

-private_key_path

At the very least, you must specify the path to an encoded private key used for establishing SSH connections. You may be able to use /etc/ssh/ssh_host_rsa_key or $HOME/.ssh/id_rsa, but it's recommended that you generate a private key for Serveo's use (using ssh-keygen, for example: ssh-keygen -t rsa -f ssh_host_rsa_key).

./serveo -private_key_path=/etc/ssh/ssh_host_rsa_key
./serveo -private_key_path=$HOME/.ssh/id_rsa

-port, -http_port, -https_port

These options tell Serveo on which ports, respectively, to listen for SSH, HTTP, and HTTPS connections.

./serveo -private_key_path=ssh_host_rsa_key -port=22 -http_port=80 -https_port=443
./serveo -private_key_path=ssh_host_rsa_key -port=2222 -http_port=8080 -https_port=8443

-cert_dir

This is necessary for HTTPS support. The directory it specifies should contain TLS certificates and keys. For example, a cert_dir might contain the following files:

    abc.crt      abc.key      foo.crt      foo.key

Certificate files must end in .crt, and keys in .key. The basename for certificate files doesn't matter, but must match the corresponding key file (i.e. abc.{crt,key} should both exist). Wildcard certificates and certificates with multiple DNS names are supported.

./serveo -cert_dir=certs

-domain

This option specifies the default domain in case no domain is specified.

./serveo -domain=example.com

-disable_telemetry

A few basic events are reported for my analytical use (process startup and the start of port forwarding). Invoke this flag to disable telemetry.