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From: hubcap@hubcap.clemson.edu (Mike Marshall)
Newsgroups: comp.unix.wizards
Subject: Re: Differences between Berkley 4.2 and 4.3
Message-ID: <7422@hubcap.clemson.edu>
Date: 14 Dec 89 14:20:39 GMT
References: <301@fltk.UUCP>
Organization: Clemson University, Clemson, SC
Lines: 19

I'm not qualified to talk about the implimentation differences, but one of
the functional differences between 4.2 and 4.3 networking can be seen in 
/usr/include/netdb.h:

struct	hostent {
	char	*h_name;	/* official name of host */
	char	**h_aliases;	/* alias list */
	int	h_addrtype;	/* host address type */
	int	h_length;	/* length of address */
	char	**h_addr_list;	/* list of addresses from name server */
#define	h_addr	h_addr_list[0]	/* address, for backward compatiblity */
};

In the above structure h_addr_list is a 4.3ism. One of the things that can
end up here is an ordered list of MX hosts. Back in the pre DNS days of 4.2
all they did was look up an address in /etc/hosts and all that was needed
was h_addr.

-Mike          hubcap@clemson.edu