Re: ip address and ports

From: Lik Mai Sak (cuddlybear101@yahoo.com)
Date: 11/27/02 

From: Lik Mai Sak <cuddlybear101@yahoo.com>
Date: Wed, 27 Nov 2002 18:49:37 +1100

Tracker wrote:

> Barry Margolin wrote:
>
> > In article <3DE3D240.2AB71359@yahoo.com>, Lik Mai Sak <alt.test> wrote:
> > >Tracker wrote:
> > >
> > >> > >having an open port
> > >> > Every PC (server, etc...) on the Internet with an IP address will have
> > >> > at least one port open.
> > >> Thousands of malicious hackers would love to get into my computer. On a
> > >> Windows Platform, no port is open, and am not running any SERVERS.
> > >
> > >Really? Go have a squizz at info/RFC's regarding ident.
> >
> > Does Windows run an IDENT server by default? I don't know for sure, but I
> > suspect not.
> >
> > >> > Your browser will, for example, open port 80.
> > >> Bullcrap, how can a browser open port 80? You really am lost dude.
> > >> I won't respond to your stupidy.
> > >> Tracker
> > >
> > >It opens port 80/8080/8081/3128 etc on the machine it's connecting to. If it
> > >didn't, web browsing would not work. (tho establishing a connection to an
> > >already open port would be more accurate)
> >
> > Connecting to a server does not cause the client machine to have an open
> > port. There will be an open socket with a local (usually ephemeral) port
> > number, but it's not really "open" -- it only processes packets that come
> > back from the server it's connected to. This port can't be used by someone
> > to get into your system, which is what someone is generally concerned with
> > when they talk about "open ports". The most someone can do is forge
> > packets that appear to be part of that connection, but this requires
> > knowing the ephemeral port number and sequence numbers that are use in the
> > connection; unless the attacker is able to sniff the traffic on the
> > connection, this will be difficult.
> >
> > --
> > Barry Margolin, barmar@genuity.net
> > Genuity, Woburn, MA
> > *** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
> > Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.
>
> Way to go, great post.
>
> Tracker

As if you understood it......
E.

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