Re: Reverse DNS RFCs and Recommendations

[Barry Shein <bzs () world std com>]

On October 30, 2013 at 19:07 Valdis.Kletnieks () vt edu (Valdis.Kletnieks () vt edu) wrote:
> On Wed, 30 Oct 2013 21:33:38 -0000, Nolan Rollo said:
>
> > So in the four examples below, 3 of them preface the IP with an alpha
> > character. Charter however, starts the rDNS off with a number. I'm not arguing
> > with anyone but what potential problems could that cause with DNS?
>
> Only if the system involved got on the net before 3com did (as RFC1123
> specifically relaxed this requirement back in 1989).
>
> And at that point, Indiana Jones would say "It belongs in a *museum*".

Back when I put Boston University on the net, pre-DNS, an accidentally
included host name with a leading digit submitted for the HOSTS.TXT
file brought down probably over half the net, many many unix systems.

There was a bug in the program which converted from the HOSTS.TXT
format to the unix /etc/hosts format. It went into a loop filling the
root partitions which in those days hung a unix system hard, and many
sites used unix systems as their main or only internet connection, no
fancy on-site routers back then.

Typically sites loaded the new HOSTS.TXT file after (or exactly at)
midnight automatically so not a lot of systems staff around to recover
which made it all the more painful.

So I heard a lot about this "no leading digits in host names rule" the
next day though when everyone calmed down it was agreed that the
conversion program shouldn't have behaved so poorly.

-- 
        -Barry Shein

The World              | bzs () TheWorld com           | http://www.TheWorld.com
Purveyors to the Trade | Voice: 800-THE-WRLD        | Dial-Up: US, PR, Canada
Software Tool & Die    | Public Access Internet     | SINCE 1989     *oo*