Return-RST is a firewalling tool for Linux 2.2.xx systems using IPCHAINS. It uses the netlink device to capture packets and sends TCP RST packets in response to TCP connection requests. Normal IPCHAINS only allows you to drop packets, or reject packets with an ICMP error message. With Return-RST, you can make it look like there is no server listening, rather than giving away that they're being filtered to the attacker.
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