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Created November 23, 2016 12:41
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Setup for an easy to use, simple reverse http tunnels with nginx and ssh. It's that simple there's no authentication at all. The end result, a single ssh command invocation gives you a public url for your web app hosted on your laptop.


A lot of times you are developing a web application on your own laptop or home computer and would like to demo it to the public. Most of those times you are behind a router/firewall and you don't have a public IP address. Instead of configuring routers (often not possible), this solution gives you a public URL that's reverse tunnelled via ssh to your laptop.

Because of the relaxation of the sshd setup, it's best used on a dedicated virtual machine just for this (an Amazon micro instance for example).


Server side:

  • a server with a public ip ( in this document)
  • a domain name (domain.tld in this document)
  • a wildcard dns entry in the domain pointing to the public ip (* 1800 IN A
  • nginx
  • sshd

Client side:

  • ssh client (even plink would work on Windows)

Nginx config

A wildcard dns should point to this nginx instance. Every www<port>.domain.tld will be proxied to<port>

Where <port> needs to be 4 or 5 digits.

server {
  server_name   "~^www(?<port>\d{4,5})\.domain\.tld$";

  location / {
    proxy_set_header  X-Real-IP  $remote_addr;
    proxy_set_header  Host $host;

SSH configuration

A sshd configuration to allow a user with no password and a forced command, so that the user can't get shell access.

Match User tunnel
  # ChrootDirectory
  ForceCommand /bin/echo do-not-send-commands
  AllowTcpForwarding yes
  PasswordAuthentication yes
  PermitEmptyPasswords yes

PAM needs to be disabled if sshd is to allow login without a password. That's not always possible, is not even smart. Another approach would be a separate instance of sshd, on a different port, just for the tunnel user.

Make a copy of the config file, change/add these settings:

UsePAM no
AllowUsers tunnel
Port 722

And then run sshd -f /etc/ssh/sshd_config_tunnel.

The tunnel user has an empty password field in /etc/shaddow.



Just connect with:

ssh -N -T -l tunnel -R 0:localhost:5050 -p 722

ssh will respond with a Allocated port 56889 for remote forward to localhost:5050 message. Then you can use www56889.domain.tld


Test ChrootDirectory in sshd

#! /bin/sh
exec 3>&1
eval ssh -N -T $ssh_server -l $ssh_user -R 0:localhost:$local_port -p $ssh_port 2>&1 1>&3 \
| sed 's|^Allocated port \([[:digit:]]\+\) for remote forward to|Your url is '$url_tmpl' will be forwarded to|'
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