Remote Mgmt

In this scenario peers initiate connections to the cerntral server, making their way through NAT and Firewalls, but you don’t want to forward their traffic.

Central Server Config

No forwarding or masquerade is desired, so there is no additional configuration to the central server.

Client Config

The remote peer - the one you created when setting up the server - is already set up with one exception; a keep-alive.

When the remote peer establishes it’s connection to the central server, intervening firewalls allow you to talk back as they assume it’s in response. However, the firewall will eventually ‘close’ this window unless the client continues sending traffic occasionally to ‘keep alive’ the connection.

# Add this to the bottom of your client's conf file
PersistentKeepalive = 20

Firewall Rules

You should apply some controls to your clients to prevent them from talking to each other (and possibly the server and you also need a rule for the admin station. You can do this by adding rules to the forward chain.

# Allow an 'admin' peer at .2 full access to others and accept their replies
sudo nft add rule inet filter forward iifname "wg0" ip saddr 192.168.100.2 accept
sudo nft add rule inet filter forward ct state {established, related} accept
# Reject any other traffic between peers
sudo nft add rule inet filter forward iifname "wg0" oifname "wg0" reject with icmp type admin-prohibited

You can persist this change by editing your /etc/nftables.conf file to look like this.

sudo vi /etc/nftables.conf

#!/usr/sbin/nft -f

flush ruleset

table inet filter {
        chain input {
                type filter hook input priority 0;
        }
        chain forward {
                type filter hook forward priority 0;

                # Accept admin traffic
                iifname "wg0" ip saddr 192.168.100.2 accept
                iifname "wg0" ct state {established, related} accept

                # Reject other traffic between peers
                iifname "wg0" oifname "wg0" reject with icmp type admin-prohibited
        }
        chain output {
                type filter hook output priority 0;
        }
}
table ip nat {
        chain postrouting {
                type nat hook postrouting priority srcnat; policy accept;
                masquerade
        }
}