Usernet Portmap Lo

Container on a user-defined network, with a port published on a loopback address

Adding a network running a container with a port mapped on a loopback address, equivalent to:

docker network create \
  -o com.docker.network.bridge.name=bridge1 \
  --subnet 192.0.2.0/24 --gateway 192.0.2.1 bridge1
docker run --network bridge1 -p 127.0.0.1:8080:80 --name c1 busybox

The filter and nat tables are identical to nat mode:

{{index . "LFilter4"}}

{{index . "SFilter4"}}

{{index . "LNat4"}}

{{index . "SNat4"}}

{{index . "LRaw4"}}

{{index . "SRaw4"}}

filterPortMappedOnLoopback adds an extra rule in the raw-PREROUTING chain to DROP remote traffic destined to the port mapped on the loopback address.