How to create a netcat relay on OS X?

Question

I'm trying to troubleshoot my postfix so I decided to route its traffic to my isp smtp relay trough a netcat relay:

nc -l <someport> 0<backpipe | nc <isp-smtp> 26 | tee backpipe

And I configured my postfix to connect to localhost:. But to get the netcat relay working it needs a FIFO pipe made with mknod backpipe p and apparently this is not supported on OS X.

Is there an alternative way to either set up a TCP relay I can monitor, or something else I can use to watch the chit-chat between postfix and my isp smtp?

Answer 1

Under Leopard, mkfifo is in /usr/bin. Not sure about prior.

/usr/bin/mkfifo backpipe

personally I'd recommend using tcpdump and/or wireshark, it gives you a nicer view of the traffic too.