type: txt
help: "use TCP syn cookies"
default: "enable"
syntax: $(@) in "enable", "disable"; "syn-cookies must be enable or disable"
update: "if [ x$(@) == xenable ]; \
                 then sudo sh -c \"echo 1 > /proc/sys/net/ipv4/tcp_syncookies\"; \
                 else sudo sh -c \"echo 0 > /proc/sys/net/ipv4/tcp_syncookies\"; fi"
delete: "sudo sh -c \"echo 1 > /proc/sys/net/ipv4/tcp_syncookies\""