Docker tips

Dockerfile

# On a docker container force to not reach Internet/connectivity
# The docker must be started as a privileged with the param --privileged and
# on the running container, you must have iptables installed (apt-get install iptables),
# then you can run:

# To avoid all connectivity at all
iptables -A OUTPUT -j DROP
# Avoid all connectivity on a specific interface
iptables -A OUTPUT -o eth1 -j DROP
# Avoid connectivity to a specific IP
iptables -A INPUT -s 1.2.3.4 -j DROP
# If the restriction must be for a specific port (for example 25), then:
iptables -A INPUT -s 1.2.3.4 -p tcp --destination-port 25 -j DROP