I'd like to temporarily turn on the echo service (TCP and UDP port 7) on in Mac OS 10.6 (Snow Leopard). I guess this involves using the
Port number 7 is traditionally labeled "echo", but AFAIK no modern OS implements it.
Note that this is completely different from the ICMP_ECHO used by
ping. That is enabled by default, although it will be blocked if the firewall is placed in stealth mode.