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Date:      Wed, 7 Nov 2001 09:56:32 +1100
From:      Edwin Groothuis <edwin@mavetju.org>
To:        ann kok <annkok2001@yahoo.com>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: service file
Message-ID:  <20011107095632.Z35710@k7.mavetju.org>
In-Reply-To: <20011106213145.74148.qmail@web20104.mail.yahoo.com>; from annkok2001@yahoo.com on Tue, Nov 06, 2001 at 01:31:45PM -0800
References:  <20011106213145.74148.qmail@web20104.mail.yahoo.com>

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On Tue, Nov 06, 2001 at 01:31:45PM -0800, ann kok wrote:
> I am wandering what is the function of the file
> 'service'

/etc/services you mean?

It's a list of known services and ports combinations. By using an
external-file, and not hardcoding all the ports in the applications,
you're adding an abstraction layer to it. And the abstraction layer
gives you the possibility to change the port-number if needed. For
example, have a look at the entry in /etc/services for radius. You
see two entries, one commented out with a remark above it.

If everybody would use hard-coded ports, it would never move to
the right port. But now all you have to do is change the entry in
/etc/services and the application is using the right ports, it's
easy to move along.

Also, finding service-names if you have only the port-number (for
example if you run tcpdump), it shows you what service is (probably)
being accessed.

Edwin

-- 
Edwin Groothuis   |              Personal website: http://www.MavEtJu.org
edwin@mavetju.org |           Interested in MUDs? Visit Fatal Dimensions:
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