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From: chris@mimsy.umd.edu (Chris Torek)
Newsgroups: comp.unix.wizards
Subject: Re: Determining one's own IP address.
Message-ID: <21234@mimsy.umd.edu>
Date: 12 Dec 89 17:59:16 GMT
References: <601@bmers58.UUCP> <4429@ur-cc.UUCP> <604@bmers58.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 19

In article <604@bmers58.UUCP> davem@bmers58.UUCP (Dave Mielke) writes:
>I would like to be able to determine my local IP address without
>involving a hosts file or yp lookup, i.e. from memory, from within a c
>program.

Since your machine might have anywhere from zero to several hundred
official IP addresses, this is not possible.

The closest thing there is to `myself' is 127.0.0.1, which (I think)
has now been officially reserved to mean `loopback' or `connect to
myself'.

4BSD provides a `gethostid' call, but what you get is not necessarily
a valid IP address.  Since we had never set our hostid under 4.2BSD
(setting it to zero, in effect), I am fairly sure that nothing in 4.2BSD
actually used it.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@cs.umd.edu	Path:	uunet!mimsy!chris