podman-wireguard

Hint: This is IPv4 only. Remove all IPv6 stuff from the wireguard-config!

Current entrypoint.sh assumptions for strict mode (egress only through wg0 + killswitch):

• Use a literal IPv4 Endpoint (Endpoint = x.x.x.x:51820), not a hostname.
• Use a single peer endpoint for this gateway container.

Wireguard container

• Entrypoint: container/entrypoint.sh
• Dockerfile: container/Dockerfile

Build it all together

podman build --pull --no-cache --tag localhost/wg-gateway-image -f container/Dockerfile .

Network container

This is IPv4 only. Remove all IPv6 settings from your WireGuard config before proceeding.

Note: If your setup supports it, you can use --userns=auto instead of explicit --uidmap/--gidmap for simpler user namespace isolation.

Rootless

Pasta provides excellent network isolation for rootless containers.

podman run --name wg-gateway \
  --detach \
  --replace \
  --pull never \
  --cap-drop ALL \
  --cap-add NET_ADMIN \
  --ipc=none \
  --security-opt no-new-privileges:true \
  --network pasta:--no-map-gw,-t,none,-u,none,-T,none,-U,none,--no-tcp,--no-icmp,--no-dhcp,--no-dhcpv6,--no-ndp,--no-ra,-4,-D,none,-S,none \
  --sysctl net.ipv4.conf.all.src_valid_mark=1 \
  --sysctl net.ipv6.conf.all.disable_ipv6=1 \
  --sysctl net.ipv6.conf.default.disable_ipv6=1 \
  --uidmap 0:10000:64 \
  --gidmap 0:10000:64 \
  --volume "$PWD"/wg0.conf:/etc/wireguard/wg0.conf:ro \
  localhost/wg-gateway-image

Rootful

Rootful mode requires an isolated bridge network to prevent unintended host access.

Create the network first:

podman network create \
  --subnet 172.20.0.0/16 \
  --disable-dns \
  --opt isolate=true \
  wg-gateway-net

Then run the container:

podman run --name wg-gateway \
  --detach \
  --replace \
  --pull never \
  --cap-drop ALL \
  --cap-add NET_ADMIN \
  --ipc=none \
  --network wg-gateway-net \
  --security-opt no-new-privileges:true \
  --sysctl net.ipv4.conf.all.src_valid_mark=1 \
  --sysctl net.ipv6.conf.all.disable_ipv6=1 \
  --sysctl net.ipv6.conf.default.disable_ipv6=1 \
  --uidmap 0:100000:64 \
  --gidmap 0:100000:64 \
  --volume "$PWD"/wg0.conf:/etc/wireguard/wg0.conf:ro \
  localhost/wg-gateway-image

Testing

Run a simple test. This should return the IP of your VPN.

podman run --rm --net=container:wg-gateway docker.io/curlimages/curl -skL --max-time 2 icanhazip.com

Cleanup

Remove the container and image when you are done:

podman rm -f wg-gateway
podman rmi -f localhost/wg-gateway-image

If you created the rootful network, remove it as well:

podman network rm -f wg-gateway-net

Extra hardening

The following options can be combined freely. Add them to your podman run command as needed.

Syscall filtering

Restrict the container to a predefined set of allowed syscalls:

--security-opt seccomp=/usr/share/containers/seccomp.json

Resource limits

Prevent resource exhaustion by capping memory and process count:

--pids-limit 10 \
--memory 10m \
--memory-swap 10m

Read-only containers

Mount the container's root filesystem as read-only:

--read-only

If the container needs a writable temp directory, add a locked-down tmpfs:

--tmpfs /tmp:rw,noexec,nosuid,size=16M

DNS on read-only containers

--dns on --net=container:... is not supported by Podman - that's why we need workarounds.

Option 1 - Via WireGuard config (entrypoint.sh writes DNS from the [Interface] block):

echo -n > resolv.conf && chmod 666 resolv.conf

chmod 666 is required so the container can write /etc/resolv.conf even with user namespace mappings.

--volume "$PWD"/resolv.conf:/etc/resolv.conf

Option 2 - Manual static DNS (set servers explicitly, skip config-based setup):

--dns 1.1.1.1 \
--dns 8.8.8.8 \
--dns 9.9.9.9 \
--env SKIP_DNS=1

entrypoint.sh treats SKIP_DNS=1 and SKIP_DNS=TRUE as enabled.

Override DNS for a single sidecar container:

podman run --rm \
  --net=container:wg-gateway \
  --volume "$PWD"/resolv.conf:/etc/resolv.conf:U,ro \
  docker.io/curlimages/curl -skL --max-time 2 icanhazip.com