Shell Programming and Scripting

Hi,

Is it possible to have 2 programs to listen in 1 port? the only job of that other program is to record or monitor down any request it recieves to that specific port.
Is that possible? Won't it cause any conflicts?

Hello,

We don't know from which listener you are talking about (someone mentioned Oracle TNS listener in one of your previous thread). I assume that a listener is someone who ultimately performs the listen() syscall, i.e. acts as TCP server.

In this case, it is not possible to start two listeners on the same Internet address (i.e the pair IP : port): the second shall fail with a "Address Already in Use" error (actually, the bind fails).

HTH,
Loïc

Hi.
Yes it is a TCP server. But it is listening to a port. port 17477. hmm... then it is not possible then huh..
Even though if the other one is like trying to catch the request only? i mean like ex.
If a request to that specific port 17477 was sent from a client the program will record that request but will not return anything while the other program will also recieve that request and will return something. Can it be done?

This may help - Top 11 Packet Sniffers

packet sniffers is of course a good idea. You may need however to interpret by hand the TCP stream if your running a proprietary protocol on top of TCP.

Another alternative is to create a proxy server that receives the packet at the well known server port 17477, do whatever action it needs to do with the packet (interpret the stream, logging etc) and forwards the packet to the real server that is running to another port, say 18488. The proxy forwards the answers from the real server back to the client. The client doesn't notice that he is not speaking to the real server.

It is nowadays easy to create such a proxy using modern scripting language, like Python for instance. I may have perhaps an example somewhere.

Cheers,
Loïc