Uncomplicated Firewall (ufw) Basic Commands

Introduction
Basic Commands
References

Introduction

We present a quick introduction to Uncomplicated Firewall (ufw), a free and open-source firewall management tool for Linux operating systems. This guide can be useful for users of the TFGrid deploying on full and micro VMs as well as other types of deployment.

Basic Commands

We show here basic commands to set a firewall on Linux with Uncomplicated Firewall (ufw).

Install ufw

Update
- ```
apt update
```
Install ufw
- ```
apt install ufw
```

Enable ufw

```
ufw enable
```

Disable ufw

```
ufw disable
```

Reset ufw

```
ufw reset
```

Reload ufw

```
ufw reload
```

Deny Incoming Connections

```
ufw default deny incoming
```

Allow Outgoing Connections

```
ufw default allow outgoing
```

Allow a Specific IP address

```
ufw allow from <IP_Address>
```

Allow a Specific IP Address to a Given Port

ufw allow from <IP_Address> to any port <port>

Allow a Port for tcp

```
ufw allow <port>/tcp
```

Allow a Port for udp

```
ufw allow <port>/udp
```

Allow a Port for tcp and udp

```
ufw allow <port>
```

Allow Ports: Examples

Here are some typical examples of ports to allow with ufw:

Allow SSH (port 22)
- ```
ufw allow ssh
```
Allow HTTP (port 80)
- ```
ufw allow http
```
Allow HTTPS (port 443)
- ```
ufw allow https
```
Allow mysql (port 3306)
- ```
ufw allow 3306
```

Allow Port Ranges

Template

ufw allow <port_range_floor>:<port_range_ceiling>

Example
- ```
ufw allow 6000:6005
```

Allow a Subnet

```
ufw allow from <subnet>
```

Allow a Subnet to a Given Port

ufw allow from <subnet> to any port <port>

Deny a Port

```
ufw deny <port>
```

Deny an IP Address

```
ufw deny <IP_Address>
```

Deny a Subnet

```
ufw deny from <subnet>
```

Block Incoming Connections to a Network Interface

ufw deny in on <network_interface> from <IP_Address>

Check Rules

Use status to check the current firewall configurations. Add verbose for more details.

```
ufw status 
```
```
ufw status verbose
```

Check Rules (Numbered)

It can be useful to see the numbering of the rules, to remove more easily a rule for example.

```
ufw status numbered
```

Delete a Rule with Number