Re: Subject: Re: Slow connections - DNS problems?
On Wed, Mar 24, 2021 at 02:44:37PM -0700, Charlie Gibbs wrote:
> I tried removing the 192.168.0.1 line along with the "search telus"
> line. I didn't notice any difference, but could this be because
> this stuff is buffered somewhere? Perhaps I need to kick something
> to make sure the new file is read.
Well, that depends entirely on what tests you performed, and what
applications you're using (the real reason why you were testing these
things in the first place).
A typical test would involve you running shell commands to perform
name lookups. Each of those commands would invoke a new process,
which would re-read nsswitch.conf and resolv.conf and so on. In that
sense, there is nothing you need to "restart". The restarting is
implicit in the fact that you are running shell commands, each one
containing a separate, standalone instance of the resolver.
If there is an already-running process that you were using to do
real-life stuff (e.g. a web browser), and you wanted to load a new
page in the already-running instance of your web browser, then the
web browser, which has its own separate, standalone instance of the
resolver (possibly even a *unique* resolver, because browsers are
special snowflakes), may have cached some information, such as the
contents of resolv.conf.
Thus, you would be well-advised to restart any running browsers, mail
transport agents, NFS servers, and so on. Any or all of these programs
that use DNS results may have cached the old resolv.conf, or the old
results from DNS (positive and negative), or all of the above.
But it all starts with an actual testing methodology of some kind, and
the transparent reporting of your testing results. "I didn't notice
any difference" is not that.
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