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--- gentoo:wireguard [2025/02/06 07:16] – willy
+++ gentoo:wireguard [2025/03/13 13:26] (current) – [WireGuard] willy
@@ Line 1: / Line 1: @@
-====== WireGuard ======
+====== J) WireGuard ======
 [[https://en.wikipedia.org/wiki/WireGuard|WireGuard]] is a modern VPN tunnel solution which is quickly taking the place of OpenVPN. Some of the strong key points of WireGuard are, beside a supposedly more secure implementation, the ease of setup and how it simply merge with the overall linux network management.
@@ Line 74: / Line 74: @@
 There are tons of WireGuard tutorials online on how to use WireGuard to connect your mobile device securely to your home network, i do not plan to cover this topic here.
-===== Port Forwarding =====
-Using WireGuard for port-forwarding between an external, public accessible host, and an internal non-accessible host (like behind a CGNAT) is a less known topic and i will cover it here.
-You will need to use NFTables, see [[[[gentoo:nft|here]] for more details to better understand the following.
-Assumptions:
-  * You have one **internal** host which is behind CGNAT, and is not accessible from the internet
-  * You have one **external** host which has a public IP address
-  * Both hosts have WireGuard setup according to the configuration above
-  * Internal host expose port 22, 80 and 8443
-  * External host needs to route those three ports to the internal host
-  * The WireGuard subnet is //10.100.0.0/24// with internal host being 10.100.0.1 and external host 10.100.0.2
-  * External host **public** network interface is called **enp1s0**
-  * Both hosts WireGuard network iunterface is called **wg0**
-What we need to do is create nftable rules to ensure that:
-  * packets reaching external host on enp1s0 on port 2022 get routed to 10.100.0.1 port 22
-  * packets reaching external host on enp1s0 on port 80 get routed to 10.100.0.1 port 80
-  * packets reaching external host on enp1s0 on port 443 get routed to 10.100.0.1 port 8443
-  * return packets from the internal host get properly re-routed to the original sender out from enp1s0
-**Note:** see [[selfhost:nginx|here]] on why i use port 8443 instead of port 443 on the internal server. This is to differentiate //internal// connections, which have lesser security, from //external// connections which get additional SSO layers.
-What we need:
-  * A dedicated table called **wg**
-  * A **prerouting** chain to apply DNAT to incoming packes
-  * Rules to route port 2022/80/443 to the wg tunnel ports
-  * A **postrouting** chain to ensure that all reply packets are properly SNAT back to outside
-  * Return masquerading rules to ensure the return packets get sent back out of enp1s0
-Create the wg table:
-<code bash>
-nft add table ip wg
-</code>
-Create the base chains:
-<code bash>
-nft 'add chain ip wg prerouting { type nat hook prerouting priority -100 ; }'
-nft 'add chain ip wg postrouting { type nat hook postrouting priority 100 ; }'
-</code>
-Create the in-bound rules:
-<code bash>
-nft 'add rule ip wg ssh-in iifname enp1s0 dnat to tcp dport map { 2022 : 10.100.0.1 . 22 }'
-nft 'add rule ip wg ssh-in iifname enp1s0 dnat to tcp dport map { 80 : 10.100.0.1 . 80 }'
-nft 'add rule ip wg ssh-in iifname enp1s0 dnat to tcp dport map { 443 : 10.100.0.1 . 8443 }'
-</code>
-Create the SNAT return rule (the counter rule is only for debugging, you can omit that rule):
-<code bash>
-nft 'add rule ip wg ssh-out ip daddr 10.100.0.1 counter'
-nft 'add rule ip wg ssh-out ip daddr 10.100.0.1 masquerade'
-</code>
-This is the resulting NFTables setup:
-<code bash>
-nft list table wg
-table ip wg {
-        chain ssh-in {
-                type nat hook prerouting priority dstnat; policy accept;
-                iifname "enp1s0" tcp dport 2022 counter packets 1 bytes 60
-                iifname "enp1s0" dnat ip to tcp dport map { 2022 : 10.100.0.1 . 22 }
-        }
-        chain ssh-out {
-                type nat hook postrouting priority srcnat; policy accept;
-                ip daddr 10.100.0.1 counter packets 36 bytes 2140
-                ip daddr 10.100.0.1 masquerade
-        }
-}
-</code>
-nft add ip wg prerouting 'dnat to tcp dport map { 2022 : 10.70.0.1 . 22 }'

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