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diff --git a/content/blog/2021-01-07-ufw.md b/content/blog/2021-01-07-ufw.md deleted file mode 100644 index b0137cd..0000000 --- a/content/blog/2021-01-07-ufw.md +++ /dev/null @@ -1,223 +0,0 @@ -+++ -date = 2021-01-07 -title = "Secure Your Network with the Uncomplicated Firewall" -description = "A simple guide to the UFW." -+++ - -## Uncomplicated Firewall - -Uncomplicated Firewall, also known as ufw, is a convenient and -beginner-friendly way to enforce OS-level firewall rules. For those who -are hosting servers or any device that is accessible to the world (i.e., -by public IP or domain name), it's critical that a firewall is properly -implemented and active. - -Ufw is available by default in all Ubuntu installations after 8.04 LTS. -For other distributions, you can look to install ufw or check if there -are alternative firewalls installed already. There are usually -alternatives available, such as Fedora's `firewall` and the -package available on most distributions: `iptables`. Ufw is -considered a beginner-friendly front-end to iptables. - -[Gufw](https://gufw.org) is available as a graphical user interface -(GUI) application for users who are uncomfortable setting up a firewall -through a terminal. - - - -## Getting Help - -If you need help figuring out commands, remember that you can run the -`--help` flag to get a list of options. - -```sh -sudo ufw --help -``` - -## Set Default State - -The proper way to run a firewall is to set a strict default state and -slowly open up ports that you want to allow. This helps prevent anything -malicious from slipping through the cracks. The following command -prevents all incoming traffic (other than the rules we specify later), -but you can also set this for outgoing connections, if necessary. - -```sh -sudo ufw default deny incoming -``` - -You should also allow outgoing traffic if you want to allow the device -to communicate back to you or other parties. For example, media servers -like Plex need to be able to send out data related to streaming the -media. - -```sh -sudo ufw default allow outgoing -``` - -## Adding Port Rules - -Now that we've disabled all incoming traffic by default, we need to -open up some ports (or else no traffic would be able to come in). If you -need to be able to `ssh` into the machine, you'll need to -open up port 22. - -```sh -sudo ufw allow 22 -``` - -You can also issue more restrictive rules. The following rule will allow -`ssh` connections only from machines on the local subnet. - -```sh -sudo ufw allow proto tcp from 192.168.0.0/24 to any port 22 -``` - -If you need to set a rule that isn't tcp, just append your connection -type to the end of the rule. - -```sh -sudo ufw allow 1900/udp -``` - -## Enable ufw - -Now that the firewall is configured and ready to go, you can enable the -firewall. - -```sh -sudo ufw enable -``` - -A restart may be required for the firewall to begin operating. - -```sh -sudo reboot now -``` - -## Checking Status - -Now that the firewall is enabled, let's check and see what the rules -look like. - -```sh -sudo ufw status numbered -``` - -```txt -Status: active - - To Action From - -- ------ ---- -[ 1] 22 ALLOW IN Anywhere -[ 2] 22 (v6) ALLOW IN Anywhere (v6) -``` - -## Deleting Rules - -If you need to delete a rule, you need to know the number associated -with that rule. Let's delete the first rule in the table above. You'll -be asked to confirm the deletion as part of this process. - -```sh -sudo ufw delete 1 -``` - -## Managing App Rules - -Luckily, there's a convenient way for installed applications to create -files that ufw can easily implement so that you don't have to search -and find which ports your application requires. To see if your device -has any applications with pre-installed ufw rules, execute the following -command: - -```sh -sudo ufw app list -``` - -The results should look something like this: - -```txt -Available applications: - OpenSSH - Samba - plexmediaserver - plexmediaserver-all - plexmediaserver-dlna -``` - -If you want to get more information on a specific app rule, use the -`info` command. - -```sh -sudo ufw app info plexmediaserver-dlna -``` - -You'll get a blurb of info back like this: - -```txt -Profile: plexmediaserver-dlna -Title: Plex Media Server (DLNA) -Description: The Plex Media Server (additional DLNA capability only) - -Ports: - 1900/udp - 32469/tcp -``` - -You can add or delete app rules the same way that you'd add or delete -specific port rules. - -```sh -sudo ufw allow plexmediaserver-dlna -``` - -```sh -sudo ufw delete RULE|NUM -``` - -## Creating App Rules - -If you'd like to create you own app rule, you'll need to create a file -in the `/etc/ufw/applications.d` directory. Within the file -you create, you need to make sure the content is properly formatted. - -For example, here are the contents my `plexmediaserver` file, -which creates three distinct app rules for ufw: - -```config -[plexmediaserver] -title=Plex Media Server (Standard) -description=The Plex Media Server -ports=32400/tcp|3005/tcp|5353/udp|8324/tcp|32410:32414/udp - -[plexmediaserver-dlna] -title=Plex Media Server (DLNA) -description=The Plex Media Server (additional DLNA capability only) -ports=1900/udp|32469/tcp - -[plexmediaserver-all] -title=Plex Media Server (Standard + DLNA) -description=The Plex Media Server (with additional DLNA capability) -ports=32400/tcp|3005/tcp|5353/udp|8324/tcp|32410:32414/udp|1900/udp|32469/tcp -``` - -So, if I wanted to create a custom app rule called "mycustomrule," -I'd create a file and add my content like this: - -```sh -sudo nano /etc/ufw/applications.d/mycustomrule -``` - -```config -[mycustomrule] -title=My Custom Rule -description=This is a temporary ufw app rule. -ports=88/tcp|9100/udp -``` - -Then, I would just enable this rule in ufw. - -```sh -sudo ufw allow mycustomrule -``` |