Path: utzoo!utgpu!news-server.csri.toronto.edu!utcs.toronto.edu!cks
Newsgroups: comp.unix.internals
From: cks@hawkwind.utcs.toronto.edu (Chris Siebenmann)
Subject: Re: Shared libraries
Message-ID: <1991May11.100712.27111@jarvis.csri.toronto.edu>
Organization: Ziebmef home away from home
References: <1991May9.135637.5408@batcomputer.tn.cornell.edu> <172@titccy.cc.titech.ac.jp> <1991May10.134839.23763@batcomputer.tn.cornell.edu> <177@titccy.cc.titech.ac.jp>
Date: 11 May 91 14:07:13 GMT
Lines: 27

mohta@necom830.cc.titech.ac.jp (Masataka Ohta) writes:
| Comments in source code do count. But if you need more evidence, you
| should investigate gethostbyname() of 4.3BSD by yourself. When /etc/hosts
| is searched, it dose not return multiple IP addresses.
| Thus, the capability to return multiple IP addresses are added because of
| DNS.

 And this is a bug in 4.2BSD, rightfully corrected in 4.3 while they
were changing it anyways. It just so happens that it doesn't usually
matter which IP address a gethostname() returns, so few people cared
about the breakage.
 
 For specific examples:
- things which use hostnames as the permission mechanism, but compare
  internally against IP numbers; NFS mountds, careful rlogins, etc.
  If you rlogin to a machine on the "wrong" interface of a gateway
  machine, you're in trouble.
- Things which add permissions based on IPs got from hostname lookups;
  X11R4 'xhost' for example. If you xhost + a gateway machine and are
  on the "wrong" interface, it won't work very well.

 Both problems have bitten us locally; they are quite real.

--
	"Summary: ftell chases cars and howls at the moon."
			- Larry Campbell
cks@hawkwind.utcs.toronto.edu	           ...!{utgpu,utzoo,watmath}!utgpu!cks