Re: tlug: Internet connections from Linux

["Stephen J. Turnbull" <turnbull@example.com>]

>>>>> "Neil" == Neil Booth <NeilB@example.com> writes:

    Neil> You're right in that I was offline when doing it. However,
    Neil> why shouldn't I be able to type in ANY host, and it only
    Neil> complain if it can't find it when I actually use that

This is related to what I was explaining before.

    Neil> setting by trying to post something? And then it should try
    Neil> and look it up itself if I'm online. This is, after all, the
    Neil> behaviour of the Windows version.

Are you sure?  But let's assume that's true.  Netscape, although their 
extensions to HTML gave me the hink in the past, is a pretty good
citizen about complying to published APIs.  I don't know about
Windows, but Unix has an elaborate set of APIs called BIND related
to finding out Internet addresses.

One big advantage for this to Windows is actually a disadvantage.
Windows Netscape keeps _all_ the information in a local file; it
therefore controls its use and can take shortcuts, use threads (this
is a real advantage of the standardized Windows API) to background the
search, etc.  By contrast, under Unix, a properly configured host on a
well-managed network need not have an /etc/hosts at all, and normally
will have a trivial one which only names the local host and perhaps a
couple of important servers in case the DNS is down.  It is not
unusual in a heavily loaded network for the various servers to be
replicated and dynamically assigned, so the /etc/hosts approach might
actually fail.

It is unfortunate that the standard Unix API for the DNS is
gethostby{name,address}, which are blocking calls (ie, the thread
stops while the information is returned).  It is doubly unfortunate
that as yet vendors like Netscape cannot rely on Unices, including
Linux, to use standard thread APIs, so Netscape is single-threaded.
For this reason the DNS lookup is implemented as a second process so
that Netscape can work while the host is being looked up.

    Neil> The really annoying this is not only that it complains "mail
    Neil> host XXX not known", but also that you cannot leave that
    Neil> Preferences sub-screen until you put one in that it "knows"! 
    Neil> (from looking in /etc/hosts is my guess). Or you have to

No, I'm sure it does a full domain lookup out on the net.  But what
you could do to avoid all this nonsense is to configure qmail, smail,
or sendmail to handle your outgoing mail (and similar services);
you'll never need a DNS lookup for them again.  (Of course, if your
DNS resolver is misconfigured, nothing will ever leave your machine
again.)

    Neil> abort with the Cancel button and lose all other changes.

I agree this is a bug.  However, it may be the lesser of two evils, in 
that inter-process communication is complex, and a mismatch in the
communications between netscape and its DNS subprocess could lock up
netscape.

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