When I use http://repo.zabbix.com/zabbix/2.2/rhel/6/x86_64/zabbix-agent-2.2.1-1.el6.x86_64.rpm and http://repo.zabbix.com/zabbix/2.2/rhel/6/x86_64/zabbix-2.2.1-1.el6.x86_64.rpm on the last version of Centos. Every item with "net.if" became NOT_SUPPORTED.
Maybe some dependencies changed...
Could you remake rpm for the last update of Centos please ?