Trying to disable the network access for the user: 

```
[root@notebook ~]# iptables -I OUTPUT -m owner --uid-owner tempuser -j DROP
[root@notebook ~]# ip6tables -I OUTPUT -m owner --uid-owner tempuser -j DROP
Could not open socket to kernel: Address family not supported by protocol
[root@notebook ~]# 
[root@notebook ~]# iptables -I INPUT -m owner --uid-owner tempuser -j DROP
iptables: Invalid argument. Run `dmesg' for more information.
[root@notebook ~]# ip6tables -I INPUT -m owner --uid-owner tempuser -j DROP
Could not open socket to kernel: Address family not supported by protocol
[root@notebook ~]# 

```

Testing it: 

```
[root@notebook ~]# su - tempuser
[tempuser@notebook ~]$ ping google.com
ping: unknown host google.com
[tempuser@notebook ~]$ 
[tempuser@notebook ~]$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=56 time=4.80 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=56 time=4.07 ms
^C
--- 8.8.8.8 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1057ms
rtt min/avg/max/mdev = 4.071/4.439/4.807/0.368 ms
[tempuser@notebook ~]$ 
[tempuser@notebook ~]$ exit
logout
[root@notebook ~]# ping google.com
PING google.com (216.58.209.174) 56(84) bytes of data.
64 bytes from bud02s21-in-f14.1e100.net (216.58.209.174): icmp_seq=1 ttl=55 time=5.05 ms
^C
--- google.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 572ms
rtt min/avg/max/mdev = 5.059/5.059/5.059/0.000 ms
[root@notebook ~]# 

```

**Question:** how can I disable the network access for a given user under Linux? (INPUT/OUTPUT/IPv4/IPv6?) - why can I still ping IPv4 addresses with the user?