Road Warrior config with fwmark

[Bruno Wolff III]

On Tue, Nov 14, 2017 at 10:34:53 -0600,
  Bruno Wolff III <bruno at wolff.to> wrote:
>
>I have this working on my laptop, but I want to tweak my router so 
>that I don't need to have special iptables rules on my home network.

I got this fixed so I'll attach /etc/sysconfig/iptables and 
/etc/systemd/system/wireguard.service that make things work.
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# If our addresses are used by the local network, the wrong source
# address will be used for packets that initially (before marking)
# look like they should go out the local gateway will get the wrong
# source address. So we need to be prepared to rewrite it to make things
# work.
*nat
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
-A POSTROUTING ! -s 98.103.208.29/32 -o wg0 -j SNAT --to-source 98.103.208.29
COMMIT
*filter
:INPUT ACCEPT [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -i wg0 -p icmp -m icmp --icmp-type any -j ACCEPT
-A INPUT -s 98.103.208.26 -p icmp -m icmp --icmp-type any -j ACCEPT
-A INPUT -i wg0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A INPUT -s 98.103.208.24/29 -i wg0 -p tcp -m conntrack --ctstate NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -s 129.89.240.0/24 -i wg0 -p tcp -m conntrack --ctstate NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -s 10.32.2.72/32 -i wg0 -p tcp -m conntrack --ctstate NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -p udp -m udp -s 98.103.208.26 --dport 992 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-port-unreachable
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
-A OUTPUT -o lo -j ACCEPT
-A OUTPUT -o wg0 -j ACCEPT
-A OUTPUT -m mark --mark 0x1 -j ACCEPT
-A OUTPUT -j REJECT --reject-with icmp-port-unreachable
COMMIT
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[Unit]
Description=WireGuard Server

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=-/usr/sbin/ip link del dev wg0
ExecStart=-/usr/sbin/ip rule del pref 100
ExecStart=/usr/sbin/ip link add dev wg0 type wireguard
ExecStart=/usr/bin/wg setconf wg0 /etc/wireguard/config
ExecStart=/usr/sbin/ip address add 98.103.208.29/32 dev wg0
ExecStart=/usr/sbin/ip link set up dev wg0
ExecStart=/usr/sbin/ip route add default dev wg0 src 98.103.208.29 table 100
ExecStart=/usr/sbin/ip rule add not fwmark 1 pref 100 table 100
ExecStopPost=/usr/sbin/ip link del dev wg0
ExecStopPost=/usr/sbin/ip rule del pref 100

[Install]
WantedBy=multi-user.target