Re: Multiple TCP/IP servers on one host


Roger Fajman (RAF%NIHCU.BITNET@CUNYVM.CUNY.EDU)
Thu, 08 Sep 88 13:47:49 EDT


> There seems to be some convergence on the use of the domain name service
> ip address list, as a means of accessing multiple interfaces (with one
> interface per milking machine) to the same service host. A couple of
> notes, however, have mentioned reliance on a feature that is not
> supported: having the domain name service select which ip address to
> give you, thereby having the DNS do the randomization necessary to give
> load-leveling.
>
> Selection of the "correct" IP address must be done by the client (e.g.,
> telnet). The DNS has no way of knowing what use you will put the information
> to and it has no way of distinguishing multiple milking machines from
> multiple connections to different parts (i.e., different networks) on
> an internet.
>
> Dave

While it's not there now, one could imagine a domain name server having
the feature of optionally randomizing the addresses for a host with
multiple addresses. This would need to be indicated in the data base
somehow, as it might not be desirable for every host. The person
making the entry in the data base presumably knows what it is for.

I suspect that most Telnet clients do not now randomly select from a
list of addresses. They probably try them in the order in which they
appear, with the possible exception of prefering addresses on the same
network as themselves. It this is true, then something has to be
changed if there is to be load balancing. There are a lot fewer domain
name server implementations than Telnet client implementations.



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