Date: 13 Apr 2001 04:45:08 MDT From: Joshua Smith <joshua.ej.smith@usa.net> To: Andrew Hesford <ajh3@chmod.ath.cx>, Kane Tao <khtao@netforge.net> Cc: lists <lists@vivdev.com>, freebsd-questions@FreeBSD.ORG Subject: Re: [Re: Ports versus ports] Message-ID: <20010413104508.23878.qmail@nwcst330.netaddress.usa.net>
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they spoke: >Andrew Hesford <ajh3@chmod.ath.cx> wrote: >On Fri, Apr 13, 2001 at 03:08:31AM -0500, Kane Tao wrote: > The term port as refered to in networking is a device you can connect > to...e.g. a serial port > TCP/IP ports are the same thing except that they are logical > constructs...an IP port is a one of many connections that can be > established from one PC to another (PC not being the only device > possible). For example FTP tries to connect to port 21 on the other > computer. That means that on the server side there is a program (FTP > server) listening in on port 21 and waiting to respond to any requests > issued to that port. > >Technically it is a TCP port, not an IP port. As I understand it, IP >deals with the identification of machines (hence IP addresses) and the >packaging of data (IP packet structure). The TCP part of TCP/IP deals >with low-end stuff like making connections and transmitting data. Part >of this low-end is dividing a network interface into ports, for >organization of data and easy identification of services. > >Mind you, I've never read the specs on the protocols, so I can't be >sure. But this makes the most sense. I do know for certain that ports >are a TCP thing... you say "connect to TCP port 39" instead of >"connect to IP port 39". > >-- = >Andrew Hesford >ajh3@chmod.ath.cx i spoke: TCP or UDP work on OSI layer 4 (transport layer) and use "ports" to ident= ify what upper layer protocol a datagram is destined for, these are similar t= o SPX sockets if you are using novell. some well known "ports" are smtp-port 2= 5, DOOM-port 666, ldap-port 389, ftp-port 21, etc. = http://www.wakeolda.com/computers/ports.htm has a pretty good definition = of them, as well as a complete listing. IP works at layer 3 (network layer) and is responsible for logical addres= sing, so that a router or layer 3 switch will be able to identify where a packe= t is destined and make a routing decision based upon whatever routing protocol= they are using (RIP, OSPF, BGP, etc). the packet is then handed to the data-link layer to be framed and broken = into bits, then the physical to send the signal. blah blah blah blah = a serial port is a physical I/O port. see http://www.rad.com/networks/1995/rs232/rs232.htm for everything you ever wanted to know about RS-232 i.e. serial connections. hth joshua Joshua Smith, CCNA Data Center Technian USA.NET joshua.smith@corp.usa.net "Walk with me through the Universe, And along the way see how all of us are Connected. Feast the eyes of your Soul, On the Love that abounds. In all places at once, seemingly endless, Like your own existence." - Stephen Hawking - ____________________________________________________________________ Get free email and a permanent address at http://www.netaddress.com/?N=3D= 1 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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