[nos-bbs] DNS requirements

[Barry Siegfried]

["(Skip) K8RRA" <k8rra at ameritech.net> wrote]:

> On Wed, 2007-03-14 at 13:18 -0400, Steven Stimpson wrote:
>
> Example 1 - and all was good before upgrading the platform revision.
> My domain.txt was hand built for only my immediate ham neighborhood -
> and that is what failed.

Skip... when JNOS does a domain resolve operation it first looks
at the location and filename of "Dfile".  This is usually "/domain.txt"
unless it has been changed in FILES.CFG.  If it cannot resolve the
name from Dfile it will start using the domain nameservers which are
specified by the 'domain addserver' command.  Unless it has been
modified from the JNOS program of about 15 years ago, the list is
created in reverse order of adding the domain servers (seen with
'domain list'), so it is last in, first out.  If you have no domain
nameservers specified then if your hostid isn't in the domain.txt
file, it will fail to resolve.

> About the file...
>
> There are some external references in domain.txt that require
> Internet access.

I don't know what that means or why that would be.

> They are DNS server sites for ampr.org.

It's fine to use a DNS server on the internet that is authoritative
for ampr.org, however it is not at all necessary.  But, *why* would
you need to put their names in your local domain.txt file unless you
were specifying them by name in your 'domain addserver' commands
when your autoexec.nos file is read upon startup.  It is better to
specify them using their IP addresses in the 'domain addserver'
commands so that you don't have to resolve them in the local
domain.txt file first.

> Again, in my analysis I discounted the presence of these because the
> name I wanted to resolve was already present in exactly the form needed
> at the top of the table.
>
> Perhaps a shortsighted assumption?

I don't know what you man by the above.

> > I guess my question is are you sending n1ohx at n1ohx.ampr.org, or
> > steven2 at gwi.net?
> >
> > one is for amateur radio purposes and you will need an pre-compiled
> > domain.txt by an amateur authority for those purposes.
> >
> > the second is an internet address that should be looked up dynamically,
> > on-the-fly.

I don't understand why you are saying that you must look up ampr.org
hostids in a static and local domain.txt file.  ampr.org is a fully
qualified internet domain and any domain nameserver on the internet
will resolve ampr.org hostids.  If you use a local domain.txt file
you run the risk of the data in it becoming outdated at any time.

> > assuming you only have specific internet addresses that you send to
> > repeatedly, once in domain.txt they should be brought out of there
> > by default before even attempting a query over the net.

In general, it is very BAD to use a local domain.txt file for much
of anything except having a short one that has a few hostids in it
which you normally need to resolve very, very fast is ok and this
won't slow down the rest of your operation too much.  Obviously, the
larger you make your local domain.txt file, the slower NOS will
become with resolving hostids which are NOT in the file (because
NOS must first parse through the whole file before it starts using
specified domain nameservers in the 'domain list').

> It is my intent to extend DNS by way of a server on the host for
> internet addresses - but that is later...
> 
> For now I'm satisfied if my ...ampr.org addresses are resolved locally
> by only jnos.
> 
> And I appreciate your "should" statement - but it seems something fails
> before matching the domain.txt entry.

You must have a "neat" file and I suggest that if you need to update
it that you update it by hand.

> > Make sure the "Domain update" parameter is correct.
>
> Domain update is "ON".

Good gracious, why?  That is one of the worst things you can do.  Not
only does 'domain update' dump everything from the NOS cache into the
local domain.txt file, but it also dumps these entries in very sloppily
and in no particular order.  Have you ever looked at a domain.txt file
which you have allowed NOS to "update" automatically?  It's a mess, and
it contains all sorts of records in it that you *don't* need.

Why don't you need them?  Because they *change*.  Remember what I said
above:  "If you use a local domain.txt file you run the risk of the
data in it becoming outdated at any time."  Once you have a hostid in
your domain.txt file with an old and expired IP address in it, you're
finished.  You will never be able to resolve that hostid to a working
IP address again until you manually *drop* the entry from your
domain.txt file and then let a "real" domain nameserver on the
'domain list' resolve it.

> > only other thing I can offer, and to this day I don't know why
> > I have to do it, was suggested to me by ka1nnn.  Why or how it
> > works I do not know, but this NEEDS to be at the TOP of your
> > domain.txt $origin ampr.org.

It does not.  In fact, NOS has code which specifically causes any
$origin entry to be considered "missing".

> Hmmm - The "$origin ..." is missing from the domain.txt.

Good!  Leave it that way.

> Further, my doc accumulation has no reference to the record.  I
> will take some time to research and experiment with this suggestion!

The Start Of Authority (SOA) record for the domain called ampr.org
is at UCSD and maintained by Brian Kantor:

ampr.org.	345600	IN	SOA	ampr.org.	brian.ucsd.edu.
	10703130	2	36000	3600	7200000	86400

A start of authority does NOT belong in your domain.txt file and
NOS is specifically programmed to ignore an $origin entry if there
is one.  At least that is how I read the code.

> > Without that, we could not get Jnos to read .ampr.org addresses
> > from domain.txt without checking the file, before attempting to
> > resolve.

Could it be this was something that KA1NNN put into *his* version
of NOS many many years ago and something with which he may have been
experimenting?  To the best of my knowledge, and unless JNOS behavior
has been changed in this regard sometime in the past 15 years, it
doesn't behave that way.

> > There may be other things you can do with $origin

There may very well be, but not using JNOS.

> You have improved my luck Steven - THANKS.

Having better luck is always desirable!  :)

I hope the above was helpful.

73, de Barry, K2MF >>
           o
          <|>      Barry Siegfried
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