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added content to the linux cheatsheet

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Ken Schaefer 2 years ago
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      Runbooks/linux.md

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Runbooks/linux.md

@ -1,14 +1,14 @@
# Linux Stuff # Linux Stuff
## Hardening ## Install distro
1. Automatic Updates (Non-prod only) ## Post install
2. SSH Logins ```
3. Lockdown logins apt update
4. Firewall apt upgrade
```
### Automatic Updates
## Automatic Updates
To do updates manually. Don't do this on Production servers because you should have better planning to upgrade you key servers. To do updates manually. Don't do this on Production servers because you should have better planning to upgrade you key servers.
``` ```
@ -28,10 +28,37 @@ Configure the utility
dpkg-reconfigure --priority=low unattended-upgrades dpkg-reconfigure --priority=low unattended-upgrades
``` ```
### SSH Logins ## Create new sudo account
```
sudo adduser {username}
sudo usermod -aG sudo {username}
```
### Lockdown Logins ## Disable root
```
sudo passwd -l root
```
## SSH Logins
### Install openssh
```
sudo apt install openssh-server
```
### Setup key generated login
```
ssh-keygen
```
Go to client machine
```
ssh-keygen
ssh-copy-d username@ipaddress
```
### Lockdown Logins
Edit the following file in nano on the server: Edit the following file in nano on the server:
``` ```
@ -40,14 +67,98 @@ sudo nano /etc/ssh/sshd_config
Make the following changes: Make the following changes:
1. Change the **Port** to something other than 22 1. Change PasswordAuthentication to **no**
2. Uncomment **AddressFamily** 2. Change ChallengeResponseAuthentication to **no**
3. Change AddressFamily to **inet**
4. Change PermitRooLogin to **no**
5. Change PasswordAuthentication to **no**
Save the file and restart the ssh service Save the file and restart the ssh service
``` ```
sudo systemctl restart sshd sudo systemctl restart sshd
``` ```
## Static IP
```
sudo nano /etc/netplan/01-netcfg.yaml
network:
version: 2
renderer: networkd
ethernets:
ens18:
dhcp4: no
addresses:
- 192.168.5.50/24
gateway: 192.168.5.99
nameservers:
addresses: [192.168.5.25]
sudo netplan apply
```
## Fix LVM
```
sudo lvm
lvm > lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
exit
sudo resize2fs /dev/ubuntu-vg/ubuntu-lv
```
## Change HOSTNAME
```
sudo hostnamectl set-hostname {hostname}
hostnamectl
sudo nano /etc/hosts
/* change hostname in hosts file */
```
## Change timezone
```
timedatectl
timedatectl list-timezones
sudo timedatectl set-timezone America/Chicago
```
## Install Guest Agent for Proxmox
Applies only if this box is in a Proxmox server
1. Open Proxmox
2. Click Options
3. Turn on QEMU Agent
```
sudo apt install qemu-guest-agent
sudo shutdown
```
## Configure Firewall
```
sudo ufw status
sudo ufw default allow outgoing
sudo ufw default deny incoming
sudo ufw allow ssh
sudo ufw enable
```
## Install fail2ban
```
sudo apt install fail2ban
sudo cp /etc/fail2ban/fail2ban.{conf,local}
sudo cp /etc/fail2ban/jail.{conf,local}
sudo nano fail2ban.local
loglevel = INFO
logtarget = /var/log/fail2ban.log
sudo nano /etc/fail2ban/jail.local
bantime = 10m
findtime = 10m
maxretry = 5
backend = systemd
sudo systemctl restart fail2ban
sudo fail2ban-client status /* use to review banned */
```
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