TCP 7
Synopsis
- TCP port 7 is used by the Echo Protocol (RFC 862).
- Unix-like systems provide this via inetd/xinetd (e.g., the “echo-stream” service in xinetd or GNU inetutils-inetd) for network diagnostics in real deployments.
- Microsoft Windows offered an Echo server on port 7 through the “Simple TCP/IP Services” feature (e.g., Windows XP, Windows 7, Server 2003/2008), still seen in some legacy/lab environments.
- Cisco IOS exposes TCP port 7 when “service tcp-small-servers” is enabled, supplying the Echo service for testing.
- BusyBox inetd (common on embedded Linux/OpenWrt) can run an echo service on TCP port 7 when configured.
- Security note: when enabled, the Echo service has been abused for reflection/amplification and loop attacks (often with chargen on port 19), so it’s typically disabled by default.
Observed activity
Last 30 days
Detailed chart