Restrict a given network interface for a particular user using iptables on Linux

<span title='2019-09-05 05:25:05 +0000 UTC'>September 5, 2019</span> · 1 min · JC

I assume that users A and B are using the same Linux machine(s) where you are the administrator.

The following command will prevent the user with uid 1234 from sending packets on the interface eth0:

# iptables -t mangle -A OUTPUT -o eth0 -m owner --uid-owner 1234 -j DROP