Creating servers in OS X

How to create a simple echo server in OS X. Assuming that you already have MacPorts installed (and if not, why not!), install xinetd as follows:

port install xinetd

Create the file

/Library/LaunchDaemons/org.macports.xinetd.plist

with the following contents:

 Label
 org.macports.xinetd
 OnDemand
 
 Program
 /opt/local/sbin/xinetd
 RunAtLoad
 

Edit /etc/services to include the line:

myecho  7745/tcp # mcarter's weird nonsense

Edit /etc/xinetd.conf to include:

service myecho
{
        disable         = no
        socket_type     = stream
        wait            = no
        user            = root
        protocol        = tcp
        groups          = yes
        server          = /Users/mcarter/docs/echoserv/echoserv
        port    = 7745
}

Adjust the value of server to wherever you create echoserv. Create the file echoserv:

#!/bin/bash
read
echo $REPLY
exit 0

Test it out:

telnet localhost 7745
hello world

It should print out hello world, and exit. Open port 7745 on your router, and you should be able to connect remotely.