Anyone ever had this?

[Mark McDaid]

I’m am trying to set up a new ADT interface with a local hospital, where we receive ADT’s from the hospital.  I gave them port numbers for test and prod that I would like them to use to connect to Cloverleaf.  They said they can’t use those port numbers and gave me the port numbers they would like me to use.   ?????  What?   How can THEY not use ports on OUR system?  Can someone tell me if I’m just being dumb?  I’d like to be educated if I’m missing something here, because this makes no sense to me.

Thanks,

Topic

[David Barr]

I don’t think you’re being dumb. I know that some people who use Cloverleaf like to keep all of their ports unique regardless of whether the ports are local, on one remote system or on multiple remote systems. It isn’t necessary, but I guess it makes things slightly simpler if you can identify an interface by port number without having to know which IP address that port is associated with.

Another issue is that some people like to use the /etc/services file to enumerate the ports for their interfaces, and it gets confusing (and maybe broken) if you have multiple entries in /etc/services with the same port number.

[Mark McDaid]

David,

Thanks for the reply.  I guess that makes sense.  Gives me some more to think about.

Thanks,

[Chris Williams]

Mark,

Whichever side is acting as Server for a particular thread determines the port number to use. The client side of the connection has no say in the matter. The port number selected on the Server also has nothing to do with the port number used on the client system.

[Mark McDaid]

Chris,

That’s what I’ve tried telling them on multiple occasions, but I give up.  I don’t want to delay this project over port selection.  I’m just going to use the ports that they want me to use, and move on.  At least I know I’m not crazy (well, maybe just a little).   🙂

[Scott Folley]

I will echo what everyone else has said.  The client side of a TCP socket link selects ports from an ephemeral range.  Depending on what that range is, there is the possibility that they would be unable to use a port if it falls within that range (technically they can use it but it really messes things up).  The default ephemeral range on most unix systems starts at 32768 and goes up to 65535.  If, for some good reason, you needed to, you can tighten up that range in the network options but I have never run out of ports in the 1-32767 range.  For common usage I would describe the ports from 1-32767 as server ports and those above that as client ports.

This, of course, is true of unix systems.  I believe it is a good bit different on a windows system (just like everything else) but I don’t know what comprises the ephemeral range for windows.  A quick google search could probably enlighten me if I were so inclined.  🙂

[Chris Williams]

This may answer questions about ephemeral ports on different operating systems:

<a href="http://www.ncftp.com/ncftpd/doc/misc/ephemeral_ports.html&#8221; class=”bbcode_url”>http://www.ncftp.com/ncftpd/doc/misc/ephemeral_ports.html

You might also send them a copy of Networking for Dummies.

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