104 lines
2.6 KiB
Markdown
104 lines
2.6 KiB
Markdown
---
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author: "Devoalda"
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authorEmoji: 🐺
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title: "SSH"
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description: SSH and SSHD Configurations
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date: 2020-07-05T18:15:01+08:00
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draft: false
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hideToc: false
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enableToc: true
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enableTocContent: true
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tocPosition: inner
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tocLevels: ["h2", "h3", "h4"]
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image: images/postImages/SSH.png
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tags:
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- linux
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- arch
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- program
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- ssh
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series:
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- Linux Programs
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categories:
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- linux
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- program
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---
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# SSH Setup guide
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## Introduction
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SSH is an important tool as a system administrator. It allows for remote connection to your machine through a client, and the ability to control your machine from wherever you are.
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However, malicious attackers are able to do a brute force attack on your machine via SSH. Therefore, this tutorial will not only setup your ssh server, it will strengthen the server to help against unwanted brute force attacks.
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This tutorial will setup SSH on your machine on port 2222, instead of the default port 22; Disables remote root login, and also password authentication. You will be able to connect to your machine via ssh keypairs for added security, instead of entering your password.
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You will need 2 machines to use keypair authentication
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## Installation
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Install openssh and ufw with your package manager on both your local and remote machines
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```bash
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yay -S openssh ufw
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```
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## Start and enable ssh service
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```bash
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sudo systemctl start sshd
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sudo systemctl enable sshd
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```
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## Key generation
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Use Command
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```bash
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ssh-keygen -t rsa
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ssh-copy-id -i ~/.ssh/id_rsa.pub <Username>@<Remote IP Address>
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```
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Follow the prompt to generate a key, copy key to remote machines
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**REST** of the configurations below are done in the ___remote___ machine
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## SSH Configurations
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On the **remote** machine, edit sshd_config file
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```bash
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sudo vim /etc/ssh/sshd_config
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```
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Add the following configurations
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```bash
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Port 2222
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PermitRootLogin no
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AllowUsers <username>
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PasswordAuthentication no
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```
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Restart sshd service
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```
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sudo systemctl restart sshd
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```
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**Note** sshd_config file location may vary with different distros
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### Config explanation and notes
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* Port - Specify Port number to your liking
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* PermitRootLogin - Self Explanatory
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* Allow Users - Self Explanatory
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* Password Authentication - Disable Password authentication to use key
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* __Remember__ to ssh-copy-id to machine before adding this
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## Enable ufw firewall service to start on boot
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```
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sudo systemctl start ufw
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sudo systemctl enable ufw
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```
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## Firewall
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Allow ssh port on the firewall, I am using non-default ports for ssh
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```
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sudo ufw limit 2222/tcp comment 'SSH Port 2222 limit'
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```
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## Connection
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On your machine, connect to the remote machine with:
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```
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ssh -p 2222 <username>@<Remote IP Address>
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```
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