7.7 KiB
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2021-08-28 | Personal | NonRoot |
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Parent:: Selfhosting, Server Alias, Server Cloud, Server Tools
name Save
type command
action Save current file
id Save
^button-VPSConsoleSave
VPS Console Dialogue
title: Summary
collapse: open
A quick note to use command-line to interact with VPS.
style: number
Connection and initialisation
title: Summary
collapse: open
Simple commands to start using a Virtual Private Server.
Connection
ssh username@IPv4
It is usual to change password:
passwd
Initialisation and updates
sudo apt update
sudo apt upgrade
User accounts
title: Add user
~~~
sudo adduser 'username'
~~~
title: Delete user
~~~
sudo userdel -r 'username'
~~~
title: Grant admin privileges
~~~
usermod -aG sudo 'username'
~~~
Switch between user accounts
su - (username)
Reboot
Sudo reboot now
Or
sudo systemctl reboot
Change hostname
- Check the static hostname
sudo hostnamectl
- Change the hostname
sudo hostnamectl set-hostname (hostname)
Securing Server access
title: Summary
collapse: open
This section gives an overview of how to switch signing-in to a machine without having to go through typing passwords and limiting surface of brute-force attacks.
Server-side RSA preparation
2 simple commands to prepare the server:
mkdir -p ~/.ssh
chmod 700 ~/.ssh
Generating a RSA key pair
On Linux & MacOS clients, the process is simple:
ssh-keygen -t rsa
And follow the prompts.
You can then send the public key to the server:
ssh-copy-id -i ~/.ssh/(key name).pub (user)@(server)
Client's computer SSH setup
SSH Agent
In order to active SSH Agent, run:
ssh-agent $BASH
To add any key to the agent:
ssh-add ~/.ssh/(key name)
SSH script
SSH can understand scripting for ease of use. To create and edit a config file on the local machine:
touch/vim ~/.ssh/config
The declaration of a connection follows this nomenclature:
Host (scriptname) (serverIP) HostName (serverIP) IdentityFile ~/.ssh/(private key path) User (remoteusername)
Once set up, a connection can be called from Terminal with the following command:
ssh (scriptname)
Editing the Server's SSH config
To open the config file:
sudo (nano/vim) /etc/ssh/sshd_config
The following parameters enable to restrict access to the server:
// Enables SSH Key authentication PubkeyAuthentication yes
// Disables password authentication (not recommended) PasswordAuthentication no
// Disable root access (to diminish a known attack surface) PermitRootLogin no
// Disables empty passwords PermitEmptyPasswords no
// Set a Banner Banner /etc/issue.net
// Manage White/Blacklists AllowUsers (username) AllowGroups (groupname) DenyUsers (username) DenyGroups (groupname)
// Change connection Port Port xxxxx
After any change of the config file, restart the SSH service:
sudo systemctl restart sshd
Note: issue.net needs to be set:
sudo nano/vim /etc/issue.net
With a text as set out below:
Warning! Authorised use only. This server is the property of mydomain.example
Network monitoring
title: simple port monitoring
`sudo netstat -an`
title: acti r port monitoring
`sudo netstat -anp (IP/TCP/UDP)`
title: simple port stats
`sudo netstat -sp (IP/TCP/UDP)`
File management
title: Summary
collapse: open
Simple commands to access files on the server.
File navigation
title: Explore current directory
`ls -alh`
title: Change directory
`cd (folder path)`
title: Find a file
`sudo find / -iname (filename)`
Create file
touch (filepath/name)
Edit file
vi (filepath/name)
- Press 'i' for the edit mode
- 'Esc' key to exit edit mode
- Type ':wq' to save & close
Delete files & folders
title: Delete file
`rm (file path & name)`
title: Delete folder and contents
`rm -r (folder path)`
File permissions
Checking file permissions
title: Permissions
For a file: `ls -l (file path & name)`
For a folder: `ls -ld (folder path)`
Changing file permissions
title: Change permissions
`chmod xxx (folder/file path)`
For x:
- read-only: 4
- write: 2
- execute: 1
title: Change owner
`chown (owner):(group) (folder/file path)`
title: Change group
`chgrp -R (new group) (folder/file path)`
Bulk changes
title: Change file permission in a folder
`find (folder path) -type f -exec chmod xxx {} \;`
title: Change sub-folder permission in a folder
`find (folder path) -type d -exec chmod xxx {} \;`
File transfer
Instructions to use rclone for file transfers can be found Server Cloud#Cloud2Cloud.
Backing up a server
Backup preparation
Create a directory for backup:
sudo mkdir /Backup
Backup creation
Best is to launch the command from the Backup folder:
cd /Backup
Command:
sudo tar -cvpfz /Backup/backup.tar.gz --exlude=/Backup/backup.tar.gz --exlude=/proc --exlude=/tmp --exlude=/mnt --exlude=/dev --exlude=/sys --exlude=/run --exlude=/var/cache/apt/archives --exlude=/usr/src/linux-headers* --exlude=/home/*/.gvfs --exlude=/home/*/.local/share/Trash /
Once created, the backup can be transferred using the #File transfer script.
Backup cleanup
After transfer, #Delete files folders the .tar.gz file from its folder.
Backup restoring
- From the server:
sudo nc -l 1024 | sudo tar -xvpzf - -C /media/backup
- From the Client's machine, instruct:
cat (backup path & name.tar.gz) | nc -q 0 (hostname) 1024
Or through FTP:
- Send backup to the root folder over FTP
- Copy /boot/grub/menu.lst to menu.lst.bak
- Restore
sudo tar xvpfz backup.tar.gz -C / - Recreate excluded directories
mkdir proc
Mkdir lost+found
mkdir mnt
mkdir sys
...
- Replace the restored menu.lst file with the .bak created in Step 2 (dropping bak)
- MAC address may need to be change
Check
/etc/udev/rules.d/70-persistent-net.rules
Manage programs
Check if program is running
And how many instances:
sudo ps ax | grep (program)
Check what program uses a port
sudo netstar -lntup | grep (port#)
List all programs
sudo apt list --installed
Remove a package
sudo apt remove (package name)
For cleaner removal:
sudo apt purge (package name)
Documentation
title: OSXdaily
[SSH generic](https://osxdaily.com/tag/ssh/)
[All SSH commands](https://osxdaily.com/2017/02/06/list-all-terminal-commands-mac/)
[Log off user](https://osxdaily.com/2019/04/03/log-off-ssh-user/)
title: Mediatemple
[Common SSH commands](https://mediatemple.net/community/products/dv/204643550/common-ssh-commands)
title: Scripting OSX
[Intro to SSH for Mac admins](https://scriptingosx.com/2017/07/quick-introduction-to-ssh-for-mac-admins/)