Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!ig!ames!scubed!optis31!zepf
From: zepf@optis31.UUCP (Tom Zepf)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Ignorant question - multiple connections within TCP ports?
Message-ID: <640@optis31.UUCP>
Date: 19 Jul 89 22:21:05 GMT
References: <1765.AA1765@geo-works>
Reply-To: zepf@optis31.UUCP (Tom Zepf)
Organization: Optigraphics Corporation, San Diego
Lines: 25

In article <1765.AA1765@geo-works> bryan@geo-works.UUCP (Bryan Ford) writes:
>connections - correct?  However, is there a way that there can be more than
>one connection to a single port?  For example, if someone connects to port
>21 on a host to do some FTP stuff, then someone else tries to also connect
>to port 21 on the same host while the first connection is still going, what
>happens?  Does the request get denied, or does another FTP server process
>get started up, or what?

Each TCP connection in a network is distinguished by these four items:

	Peer #1 Address
	Peer #1 Port
	Peer #2 Address
	Peer #2 Port

No two connections may exist with exactly the same values. This usually
enforced by the peers' operating systems.

FTP uses the client's address and port to distinguish multiple
connections to the same server port.

-- 
Tom Zepf					Optigraphics Corporation
scubed!optis31!zepf				9339 Carroll Park Drive
seismo!esosun!optis31!zepf			San Diego, CA 92121