Tracing through ports

Posted on 2003-12-12
Last Modified: 2010-04-09
we have a POS system that is supposed to pass information from a station to the server and then the server returns information for this we had to have the upper ISS enable some ports. Now the product vendor is saying the ports aren't open.

Does anyone know if there's a way to send info out through on port so it will hit the server and return through another port, and let us know where it's getting blocked? whether on the outgoing or incoming?
Question by:Trollios
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LVL 45

Expert Comment

ID: 9929174
Hi Trollios,

What platform are you using?
Are you going through a firewall or proxy?


Author Comment

ID: 9929362
I would assume it's Sisco. It's just a piece of hardware, that we can't get to.

We have a two-tiered ISS, there's the upperlevel that controls the major servers and there's us that handle smaller servers and workstations.

and it is a firewall.
LVL 45

Expert Comment

ID: 9929777
Hi Trollios,

It sounds to me that the ports probably are opened at most junctions, but the firewall has a rule preventing the connection from the "outside".

Just a guess....

Good Luck,

Author Comment

ID: 9929831
Thanks Kent.

but do you know if there's software that can find out for me for sure?
LVL 45

Accepted Solution

Kdo earned 400 total points
ID: 9930131
Hi Trollios,

There are quite a number of "port scan" solutions out there, but that's probably overkill.

From the two machines in question (the client and the server), can you ping each other?  If so, then basic connectivity is OK.

Is telnet, ftp, ssh or some other protocol/service available that will let you connect from one system to the other?  If so log onto each system and create a connection to the other.  If succesful, so far so good.  :)

If telnet or http is open, use a telnet or browser session to connect to the troublesome port on the other system.  The error messages that you get here should indicate who/what is the trouble.

telnet <ipaddress> [port]


Good Luck,

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