> It is like a port knocking service but a little bit different: > > Normaly a port knocking service uses TCP/UDP, but openportd > uses ICMP echo response packets because they are not so easy > to send like echo requests or TCP/UDP port tests (kiddies could > simply use ping or nmap for this job). > > You can define keys and actions in /etc/openportd.conf. If a > key is received, an action is executed. Here are examples: > > 04t3904jg034 reboot > 0987654321 pkill sshd > 1234567890 /usr/sbin/sshd > 40tg340503n5 pf/iptables (load some other rules or whatever)
This sounds like authpf done on a trip. And do you really mean to kill sshd upon receiving an ICMP packet?!