--- title: Wireguard --- ## Installation `# pacman -S wireguard-tools` *Enable backports for buster and older* `# apt install wireguard` ## Configuration This command creates a private key and also a matching public key `$ wg genkey | tee (name).key | wg pubkey > (name).pub` The network we will be using for wireguard will be 172.16.1.0/24 To activate a wireguard tunnel on boot use the following command `# systemctl enable --now wg-quick@wg0.service` ### VPN "Server" configuration *Illustration only, don't share your private keys* Private key: `oFlgQ3uq4tjgRILDV3Lbqdx0mVZv2VCWWRkhJA3gcX4=` Public key: `/0LMRaQCx1oMIh+eU/v4T3YQ8gAb/Qf7ulYl0zzFAkQ=` This server needs to have a public IP. All traffic between the different nodes will be routed through here. Kernel forwarding has to be enabled SystemD only loads settings specified in the `/etc/sysctl.d/` directory `# echo "net.ipv4.ip_forward=1" >> /etc/sysctl.d/80-forwarding.conf` `# sysctl -p /etc/sysctl.d/80-forwarding.conf` Note how the first peer has two allowed IPs. `/etc/wireguard/wg0.conf` ``` [Interface] Address = 172.16.1.10/24 ListenPort = 51900 PrivateKey = oFlgQ3uq4tjgRILDV3Lbqdx0mVZv2VCWWRkhJA3gcX4= MTU = 1420 PostUp = /etc/wireguard/wg0-postup.sh PostDown = /etc/wireguard/wg0-postdown.sh [Peer] PublicKey = r+TAbAN1hGh4MaIk/J5I5L3ZSAn+kCo1MJJq5YxHrl0= AllowedIPs = 172.16.1.100/32, 172.16.1.69/32 [Peer] PublicKey = RYXavpsPkJ8jwiBI39kz1csqgMDtVK14Lo2u8pDL0UY= AllowedIPs = 172.16.1.101/32 [Peer] PublicKey = 0jDtfR5GlZAHWtwxVEpukjneVj/Ace40VVdHh/eZnwU= AllowedIPs = 172.16.1.200/32 ``` `/etc/wireguard/wg0-postup.sh` ``` WIREGUARD_INTERFACE=wg0 WIREGUARD_LAN=172.16.1.0/24 MASQUERADE_INTERFACE=ens33 iptables -t nat -I POSTROUTING -o $MASQUERADE_INTERFACE -j MASQUERADE -s $WIREGUARD_LAN # Add a WIREGUARD_wg0 chain to the FORWARD chain CHAIN_NAME="WIREGUARD_$WIREGUARD_INTERFACE" iptables -N $CHAIN_NAME iptables -A FORWARD -j $CHAIN_NAME # Accept related or established traffic iptables -A $CHAIN_NAME -o $WIREGUARD_INTERFACE -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT # Accept traffic from (source) to (destination) #iptables -A $CHAIN_NAME -s 172.16.1.100 -i $WIREGUARD_INTERFACE -d 172.16.1.10 -j ACCEPT #iptables -A $CHAIN_NAME -s 172.16.1.101 -i $WIREGUARD_INTERFACE -d 172.16.1.10 -j ACCEPT #iptables -A $CHAIN_NAME -s 172.16.1.200 -i $WIREGUARD_INTERFACE -d 172.16.1.10 -j ACCEPT #iptables -A $CHAIN_NAME -s 172.16.1.200 -i $WIREGUARD_INTERFACE -d 172.16.1.100 -j ACCEPT # Accept all traffic on the wireguard network iptables -A $CHAIN_NAME -s 172.16.1.0/24 -i $WIREGUARD_INTERFACE -j ACCEPT # Drop everything else coming through the Wireguard interface iptables -A $CHAIN_NAME -i $WIREGUARD_INTERFACE -j DROP # Return to FORWARD chain iptables -A $CHAIN_NAME -j RETURN ``` `/etc/wireguard/wg0-postdown.sh` ``` WIREGUARD_INTERFACE=wg0 WIREGUARD_LAN=172.16.1.0/24 MASQUERADE_INTERFACE=ens33 CHAIN_NAME="WIREGUARD_$WIREGUARD_INTERFACE" iptables -t nat -D POSTROUTING -o $MASQUERADE_INTERFACE -j MASQUERADE -s 172.16.1.0/24 # Remove and delete the WIREGUARD_wg0 chain iptables -D FORWARD -j $CHAIN_NAME iptables -F $CHAIN_NAME iptables -X $CHAIN_NAME ``` ### VPN "Client" configuration *Illustration only, don't share your private keys* Private key: `kAgCeU6l+RWlFxfpnGj19tzEDyYz3I4HuqHkaUmHX1Q=` Public key: `r+TAbAN1hGh4MaIk/J5I5L3ZSAn+kCo1MJJq5YxHrl0=` Here we have two different interfaces configured under the same wireguard config `/etc/wireguard/wg0.conf` ``` [Interface] Address = 172.16.1.100/24 ListenPort = 51900 PrivateKey = kAgCeU6l+RWlFxfpnGj19tzEDyYz3I4HuqHkaUmHX1Q= MTU = 1420 [Interface] Address = 172.16.1.69/24 ListenPort = 51900 PrivateKey = kAgCeU6l+RWlFxfpnGj19tzEDyYz3I4HuqHkaUmHX1Q= MTU = 1420 [Peer] PublicKey = /0LMRaQCx1oMIh+eU/v4T3YQ8gAb/Qf7ulYl0zzFAkQ= AllowedIPs = 172.16.1.0/24 Endpoint = 10.80.4.124:51900 #IPv4 #Endpoint = 864f:909a:4779::b:5e1b:51900 #IPv6 PersistentKeepalive = 5 ``` ## Iptables no local access ssh user > [Block outgoing network access for single user](https://www.cyberciti.biz/tips/block-outgoing-network-access-for-a-single-user-from-my-server-using-iptables.html) > [Restrict internet access for user](https://unix.stackexchange.com/questions/21650/how-to-restrict-internet-access-for-a-particular-user-on-the-lan-using-iptables)