in the name of god, the most beneficent, the most merciful

ssh: server and dynamic port forwarding

running sshd

keep in mind that running sshd on ubuntu, starts server in current user scope, and won’t start it system-wide. thus, when running these commands:

  1. /usr/sbin/sshd and then

  2. systemctl start sshd

you get inactive as the response. so, to start server system-wide just run the following command:

systemctl start <sshd | ssh>

now, after running system status sshd command, you’ll find its status changed to active.

This is only done to ease management of ssh server through systemctl commands

sshd.service not found on ubuntu

  1. sudo apt purge openssh-server

  2. sudo apt install openssh-server -y

here, the purge command is what makes the difference.

ssh config file

when you start system-wide ssh server through systemctl, you should edit global config file which is usually located in /etc/ssh/sshd_config/.

configuring server through sshd -f <your-config-file> is done only when you start client-wide ssh server.

which key where

small reminder here

  • remote hostkey → local known_hosts

  • local publickey → remote authorized_keys

dynamic port forwarding

to configure dynamic port forwarding, ssh makes use of socks protocol. thus general syntax is:

ssh -D <local-port> <remote-username>@<remote-host>

then i wanted to enter something like this in firefox search bar

localhost:8000

to get into my vmware machine, but firefox wouldn’t allow me to. after some searching, i’ve found this issue described here

https://unix.stackexchange.com/questions/532292/browsing-localhost-via-ssh-socks-tunnel-not-working

the thing is, is that firefox browser won’t tunnel localhost address through proxy, thus you need to change firefox internal configuration in order to force it:

  1. type about:config in search bar, then accept all risks and continue

  2. change network.proxy.allow_hijacking_localhost to true

that’s it. now you can proxy you localhost address w/ firefox. but keep in mind that these settings vary between different browsers.

recommended book: ssh - oreilly

https://www.oreilly.com/library/view/ssh-the-secure/0596008953/