How to enable echo service for tcp or udp on well-known port 7 on Mac OS X 10.8 or above? I am learning TCP/IP protocol with a Mac, and need echo service (refer to [RFC 862], or Wiki) to test network. But it seems to OS X doesn't implement it or disable it.

I learned that launchd replaced inetd, you can create a launchd Property List File to launch daemons. In that way you can control some network service. So i edited telnet.plist (located in /System/Library/LaunchDaemons), set "Disabled" to "NO", and successfully enable telnet service. But I don't find echo.plist or something similar.

Or, I can create an echo.plist according to telnet.plist


But what ProgramArguments should be? Is there a built-in daemon for echo service of which name maybe echod?

Or, I have to compile inetd from source?

Thanks for any advice.
AFAIK the echo service isn't implemented in OS X. You may use either a Java echo client/server or CocoaEcho instead.

After unzipping the file check the folder .../build/Debug. I tested CocoaEcho server/client in 10.9.5 and it still works though it was built for 10.7. If you use a newer OS X version you may have to recompile it.