Echo
A trivial debug service on 7/tcp+udp that echoes back whatever you send. Rarely useful beyond confirming a host is up — but the UDP variant is a classic DoS-amplification and 'echo-chargen' loop source.
Ports
| Port | Proto | Notes |
|---|---|---|
7 | tcp | echo |
7 | udp | echo (amplification) |
Fingerprint
- Whatever you send is returned verbatim
- nmap -sV labels it echo
Exploitation primitives
- Liveness check / confirms an inetd-style stack is running
- UDP echo ↔ chargen (19) can be looped for traffic amplification (DoS)
Overview
Echo on 7 just reflects input. There’s almost no offensive value beyond fingerprinting an old inetd host and noting the UDP amplification risk.
Enumeration
echo "ping" | nc -nv <TARGET> 7Hardening
Disable the echo (and chargen/daytime/discard) inetd services — they’re obsolete and abusable for amplification.