-`vim /etc/ssh/sshd_config` add line `PasswordAuthentication off` and then `systemctl restart ssh`
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## Firewall
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### What is a firewall
### What is a firewall?
A firewall is a system used to secure a subnet by only allowing some sort of communication (usually by closing incoming connections on specific ports)
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### Porte TCP/UDP
### TCP/UDP ports
Ports are how we interface with our server, and with services in general.
While some port numbers are assigned to specific services (e.g. websites are commonly served on port 80) there are thousands of ports available to us to run our services.
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### Why struggle over a firewall
### Why struggle over a firewall?
**Security!** It helps minimize security risks coming from vulnerabilities in the software you host, which may allow unauthorized remote access and privilege escalation.
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Security
- Minimize security risks coming from vulnerability in softwares on the machine (privilege escalation)
### Uncomplicated FireWall (UFW)
We will use it to set up a simple firewall by editing **iptables** (rules to manage network traffic).
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### UFW
### Configurazione firewall
Uncomplicated FireWall
- Software used to set up a simple firewall by editing iptables (rules to manage network traffic)
