Unable to add a new block for an ip via CSF? Iptables modules are not loaded into your server’s kernel. If you’re getting the following error on a OpenVZ VPS server: iptables: No chain/target/match by that name ACCEPT  udp opt — in !lo out *  0.0.0.0/0  -> 0.0.0.0/0  state NEW udp dpt:953 Contact the DC [...]