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9.1 KiB
9.1 KiB
| Alias | Tag | Date | DocType | Hierarchy | TimeStamp | location | CollapseMetaTable | ||||||||
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2021-08-28 | Personal | NonRoot |
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^Top
Parent:: Selfhosting, Server Alias, Server Cloud, Server Tools, Server VPN
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
~~~bash
ssh username@IPv4
~~~
It is usual to change password:
~~~bash
passwd
~~~
Initialisation and updates
~~~bash
sudo apt update && sudo apt upgrade
~~~
User accounts
title: Add user
~~~bash
sudo adduser 'username'
~~~
title: Delete user
~~~bash
sudo userdel -r 'username'
~~~
title: Grant admin privileges
~~~bash
usermod -aG sudo 'username'
~~~
Switch between user accounts
~~~bash
su - (username)
~~~
Reboot
~~~bash
sudo reboot now
~~~
Or
~~~bash
sudo systemctl reboot
~~~
Change hostname
- Check the static hostname
~~~bash
sudo hostnamectl
~~~
- Change the hostname
~~~bash
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
#^Top 2 simple commands to prepare the server:
~~~bash
mkdir -p ~/.ssh
~~~
~~~bash
chmod 700 ~/.ssh
~~~
Generating a RSA key pair
#^Top On Linux & MacOS clients, the process is simple:
~~~bash
ssh-keygen -t rsa
~~~
And follow the prompts.
You can then send the public key to the server:
~~~bash
ssh-copy-id -i ~/.ssh/(key name).pub (user)@(server)
~~~
Client's computer SSH setup
SSH Agent
In order to active SSH Agent, run:
~~~bash
ssh-agent $BASH
~~~
To add any key to the agent:
~~~bash
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:
~~~bash
touch/vim ~/.ssh/config
~~~
The declaration of a connection follows this nomenclature:
~~~bash
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:
~~~bash
ssh (scriptname)
~~~
Editing the Server's SSH config
#^Top To open the config file:
~~~bash
sudo (nano/vim) /etc/ssh/sshd_config
~~~
The following parameters enable to restrict access to the server:
~~~javascript
// 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:
~~~bash
sudo systemctl restart sshd
~~~
Note: issue.net needs to be set:
~~~bash
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
~~~bash
sudo netstat -an
~~~
title: active port monitoring
~~~bash
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
~~~bash
ls -alh
~~~
title: Change directory
~~~bash
cd (folder path)
~~~
title: Find a file
~~~bash
sudo find / -iname (filename)
~~~
Create file
~~~bash
touch (filepath/name)
~~~
Edit file
~~~bash
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
~~~bash
rm (file path & name)
~~~
title: Delete folder and contents
~~~bash
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
~~~bash
chmod xxx (folder/file path)
~~~
For x:
- read-only: 4
- write: 2
- execute: 1
title: Change owner
~~~bash
chown (owner):(group) (folder/file path)
~~~
title: Change group
~~~bash
chgrp -R (new group) (folder/file path)
~~~
Bulk changes
title: Change file permission in a folder
~~~bash
find (folder path) -type f -exec chmod xxx {} \;
~~~
title: Change sub-folder permission in a folder
~~~bash
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:
~~~bash
sudo mkdir /Backup
~~~
Backup creation
Best is to launch the command from the Backup folder:
~~~bash
cd /Backup
~~~
Command:
~~~bash
sudo tar -cvpzf /Backup/backup.tar.gz --exclude=/Backup/backup.tar.gz --exclude=/proc --exclude=/tmp --exclude=/mnt --exclude=/dev --exclude=/sys --exclude=/run --exclude=/var/cache/apt/archives --exclude=/usr/src/linux-headers* --exclude=/home/*/.gvfs --exclude=/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:
~~~bash
sudo nc -l 1024 | sudo tar -xvpzf - -C /media/backup
~~~
- From the Client's machine, instruct:
~~~bash
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
~~~bash
sudo tar xvpfz backup.tar.gz -C /
~~~
- Recreate excluded directories
~~~bash
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:
~~~bash
sudo ps ax | grep (program)
~~~
Check what program uses a port
~~~bash
sudo netstar -lntup | grep (port#)
~~~
List all programs
~~~bash
sudo apt list --installed
~~~
Remove a package
~~~bash
sudo apt remove (package name)
~~~
For cleaner removal:
~~~bash
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/)