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Symbolics vs the Domain system
Has anyone found a good solution for the following problem?
A user on a Symbolics is accessing some random INTERNET host to retrieve
some files -- but the nameserver for that host doesn't have HINFO or WKS
records -- sooo things like show directory will only list the filenames
(not the dates). This often makes it difficult to tell if the file you
want is newer than the version you have.
Often the user knows what the remote system type is but it appears that
there is no way to tell Genera. For example, if the WKS records are not
present the user is prompted for the protocol to use, but if the HINFO
record is not present you are not prompted for the machine type.
The answer does not appear to be to requre the remote hosts to have WKS
and HINFO records (see the message below). If anyone has any suggestions
on how to deal with this type of problem I'd love to hear them.
P.S. this is a response to a message I sent on tcp-ip in which I mentioned
that Genera appeared to use the WKS and HINFO records.
To quote scripture (RFC 1123, section 2.2):
An application SHOULD NOT rely on the ability to locate a WKS
record containing an accurate listing of all services at a
particular host address, since the WKS RR type is not often used
by Internet sites. To confirm that a service is present, simply
attempt to use it.
The Symbolics implementation is wrong. (I still put in WKS records, and
make some attempt to keep them up-to-date, but that's more for human use --
"gee, what services does this bogus host over here support" -- than for
Although not explicitly forbidden by the Hosts Requirements RFCs, I think
that the use of HINFO records to determine machine and operating system type
falls into the same category as above. I also still put in HINFO records,
again as an aid to other system admins who might be trying to figure out
why one of my machines is pelting them with packets, or otherwise causing
them problems. ("Jeez, that's a Brand X machine, no wonder those mail
headers look so hopeless...")
No doubt I will neither be the first nor the last to point this out.