Re: IP Addressing Problems: on my laptop Ben Laurie (ben@algroup.co.uk)
Tue, 12 Jan 1999 19:11:40 +0000

Mark S. Miller wrote:
> >It was never the case that an IP address mapped to a host. It was rather
> >the case that an IP address mapped to a host *interface*.
>
> [#] Java's networking API has no notion of host interface vs host.
> As far as I can tell.

Hang on - no networking API has a notion of hosts _or_ interfaces. They have a notion of IP numbers, surely? An IP number maps to an interface (maybe - for example, transparent proxies will map different ports on the same IP to different IPs behind the proxy!) and an interface maps to a host.

It seems to me that if A is currently talking to B and wants to be able to talk to B again in the future, then it is up to B to tell A how to do that (e.g. "use domain name X" or "connect to port Y on IP Z" or "make a query with contents V to domain name W" [this last being a bit scary, but might include, for example, LDAP queries]). A cannot guess by looking at B's hostname, IP address or DNS.

BTW, apologies for not using this [#,?,...] stuff - where is it defined?

Cheers,

Ben.

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