Run:
$ docker run --detach \
--net=host --cap-add=NET_ADMIN --cap-add=NET_RAW \
--volume /var/run/docker.sock:/var/run/docker.sock \
--volume /run/xtables.lock:/run/xtables.lock \
tozd/external-ip
After that, if any other Docker container has an environment variable EXTERNAL_IP set, with an IP address to use for
containers external IP, iptables will be configured to route container's traffic from that external IP.
The external IP must be assigned on the host.
A chain named EXTERNAL_IP is created in the nat table into which all the rules are added.
And one more empty chain is created after this one for any additional custom rules you might want
to add, named AFTER_EXTERNAL_IP.
Please make sure /run/xtables.lock exists on the host before starting the container.
This file ensures iptables locking is consistent between the host and the container,
preventing race conditions that can cause containers to fail to start.
If this file does not exist, Docker will incorrectly create it as a directory, which may cause issues both on the host and with the container.
=======
docker-compose example
version: '3'
services:
nat_manager:
image: tozd/external-ip:ubuntu-bionic
volumes:
- /var/run/docker.sock:/var/run/docker.sock
- /run/xtables.lock:/run/xtables.lock
network_mode: host
cap_add:
- NET_ADMIN
- NET_RAW
a:
image: byrnedo/alpine-curl
command: "-s http://ifconfig.me"
environment:
EXTERNAL_IP: XX.XX.XX.XX
b:
image: byrnedo/alpine-curl
command: "-s http://ifconfig.me"
environment:
EXTERNAL_IP: YY.YY.YY.YY
Set XX.XX.XX.XX and YY.YY.YY.YY to your external IP address.