iptables -I OUTPUT 1 -p tcp --syn --dport 80 -m owner --uid-owner 777 -j DROP
pkts bytes target prot opt in out source destination
0 0 DROP tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 flags:0x17/0x02 owner UID match 777
Where 777 USERID