Added wireguard firewalling on FreeBSD blog article

content/blog/freebsd/wireguard-firewall.md

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+---
+title: Wireguard firewalling on FreeBSD
+description: How to configure pf for wireguard on FreeBSD
+date: 2023-03-15
+tage:
+- pf
+- vpn
+- wireguard
+---
+
+## Introduction
+
+There are multiple firewall solutions available on FreeBSD, but I only ever used pf. If you are a ipfw or ipfilter user I am sorry but I trust you will know how to translate the firewalling rules.
+
+## Template for this article
+
+```cfg
+scrub in all
+
+table <jails>    persist
+table <myself>   const { self }
+table <private>  const { 10/8, 172.16/12, 192.168/16, fd00::/8 fe80::/10 }
+table <internet> const { 0.0.0.0/0, !10/8, !172.16/12, !192.168/16, ::/0, fe80::/10, !fd00::/8 }
+
+##### Basic rules #####
+nat  pass  on  egress  from  <jails>  to  <internet>  ->  (egress:0)
+rdr-anchor "rdr/*"
+set skip on lo
+block return log
+
+##### This firewall #####
+block drop in on egress
+pass inet proto icmp all icmp-type unreach code needfrag  # MTU path discovery
+pass inet proto icmp all icmp-type { echoreq, unreach }   # echo reply
+pass inet6 proto icmp6 all
+
+pass in on egress proto tcp from <internet> to <myself> port { ssh, http, https, smtp, smtps, submission }
+pass out from <myself> to any
+```
+
+A pre-requisite of this configuration is to have set an `egress` group for your egress interface(s) like so in your `/etc/rc.conf`:
+```cfg
+ifconfig_vtnet0="DHCP group egress"
+```
+
+## Client only
+
+With our template, you can already use your wireguard vpn as a client without any changes because of the `pass out from <myself> to any` rule. It cover all outgoing traffic for us:
+- egress udp to port 342 (the port we used as example in our previous articles) to establish the tunnel with our peers
+- egress from interface wg0 to send packets into the tunnel.
+- conveniently, it covers both ipv4 and ipv6
+
+## Reachable client
+
+To make your client reachable over wireguard, add the following:
+```
+pass in on wg0 from <private> to <myself>
+```
+
+## Server
+
+A server's configuration just need to accept wireguard connections in addition of the previous rule:
+```cfg
+pass in on egress proto udp from <internet> to <myself> port 342
+pass in on wg0 from <private> to <myself>
+```
+
+## Hub
+
+As seen in a previous routing article, a hub is a server that can route traffic to another one over wireguard:
+```cfg
+pass in on egress proto udp from <internet> to <myself> port 342
+pass in on wg0 from <private> to <private>
+```
+
+Note that you will need to have set `gateway_enable="YES"` in your `/etc/sysctl.conf` to route traffic.