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# FAQ

Here are some frequently asked questions or errors about `wg-easy`. If you have a question that is not answered here, please feel free to open a discussion on GitHub.

## How do I restrict client access to specific networks or servers?

Use the Per-Client Firewall feature to enforce server-side restrictions on what each client can access.

Requirements: This feature requires `iptables` (and `ip6tables` for IPv6) to be installed on the host system.

1. Enable "Per-Client Firewall" in Admin Panel → Interface
2. Edit a client and configure "Firewall Allowed IPs"
3. Specify which destinations the client should be allowed to access

Unlike "Allowed IPs" which only controls client-side routing, firewall rules are enforced by the server and cannot be bypassed.

See the Admin Panel Guide and Client Guide for detailed configuration.

## Error: WireGuard exited with the error: Cannot find device "wg0"

This error indicates that the WireGuard interface `wg0` does not exist. This can happen if the WireGuard kernel module is not loaded or if the interface was not created properly.

To resolve this issue, you can try the following steps:

1. Load the WireGuard kernel module: If the WireGuard kernel module is not loaded, you can load it manually by running:

       sudo modprobe wireguard

2. Load the WireGuard kernel module on boot: If you want to ensure that the WireGuard kernel module is loaded automatically on boot, you can add it to the `/etc/modules` file:

       echo "wireguard" | sudo tee -a /etc/modules

## can't initialize iptables table `nat': Table does not exist (do you need to insmod?)

This error indicates that the `nat` table in `iptables` does not exist. This can happen if the `iptables` kernel module is not loaded or if the `nat` table is not supported by your kernel.

To resolve this issue, you can try the following steps:

1. Load the `nat` kernel module: If the `nat` kernel module is not loaded, you can load it manually by running:

       sudo modprobe iptable_nat

2. Load the `nat` kernel module on boot: If you want to ensure that the `nat` kernel module is loaded automatically on boot, you can add it to the `/etc/modules` file:

        echo "iptable_nat" | sudo tee -a /etc/modules

## can't initialize ip6tables table `nat': Table does not exist (do you need to insmod?)

This error indicates that the `nat` table in `ip6tables` does not exist. This can happen if the `ip6tables` kernel module is not loaded or if the `nat` table is not supported by your kernel.

To resolve this issue, you can try the following steps:

1. Load the `nat` kernel module: If the `nat` kernel module is not loaded, you can load it manually by running:

       sudo modprobe ip6table_nat

2. Load the `nat` kernel module on boot: If you want to ensure that the `nat` kernel module is loaded automatically on boot, you can add it to the `/etc/modules` file:

        echo "ip6table_nat" | sudo tee -a /etc/modules

## can't initialize iptables table `filter': Permission denied

This error indicates that the `filter` table in `iptables` cannot be initialized due to permission issues. This can happen if you are not running the command with sufficient privileges.

To resolve this issue, you can try the following steps:

1. Load the `filter` kernel module: If the `filter` kernel module is not loaded, you can load it manually by running:

       sudo modprobe iptable_filter

2. Load the `filter` kernel module on boot: If you want to ensure that the `filter` kernel module is loaded automatically on boot, you can add it to the `/etc/modules` file:

       echo "iptable_filter" | sudo tee -a /etc/modules

## can't initialize ip6tables table `filter': Permission denied

This error indicates that the `filter` table in `ip6tables` cannot be initialized due to permission issues. This can happen if you are not running the command with sufficient privileges.

To resolve this issue, you can try the following steps:

1. Load the `filter` kernel module: If the `filter` kernel module is not loaded, you can load it manually by running:

       sudo modprobe ip6table_filter

2. Load the `filter` kernel module on boot: If you want to ensure that the `filter` kernel module is loaded automatically on boot, you can add it to the `/etc/modules` file:

        echo "ip6table_filter" | sudo tee -a /etc/modules

## Clients lose connectivity after restarting the container when using multiple networks?

When you attach multiple Docker networks (e.g., `wg` and a reverse proxy network like `traefik` or `nginx`) to the `wg-easy` container, Docker might assign the network interfaces randomly (e.g., swapping `eth0` and `eth1`). Since `wg-easy` expects the wireguard interface to act as `eth0` and configures `POSTROUTING` rules for it, connectivity will break if the interfaces are swapped upon container restart.

To solve this, specify the `interface_name` and `gw_priority` explicitly in your `docker-compose.yml` file to guarantee that the `wg` network always binds to `eth0` and acts as the default gateway.

Example `docker-compose.yml`:

    services:
        wg-easy:
            # ... other configuration ...
            networks:
                wg:
                    interface_name: eth0
                    gw_priority: 1
                    ipv4_address: 10.42.42.42
                nginx:
                    interface_name: eth1
                    gw_priority: 0

    networks:
        wg:
            # ... wg network config ...
        nginx:
            external: true