http://$sum(7,18,-9.4) ??

Joseph S D Yao jsdy at
Tue Nov 2 21:55:34 UTC 1999

Barry Margolin responded:
> In article <7vl8gd$rc6$1 at>,  <aldenr at> wrote:
> >Hiya,
> >    I am a little confused with this URL ( http://$sum(7,18,-
> >9.4) ) . I was wondering whether any of the guys on this
> >channel had any idea on how something like this can be done. I think
> >that there is some DNS trickery taking place in the background. Any
> >clues ?
> The domain has the following entry:
> *	7200	A
> So if you put anything before "" other than weller, localhost,
> namnsdag, or getz (the names that are explicitly listed in the domain) it
> will use this entry.

There's a wee bit more to it.  The URL as given looks for a host name:
	$sum(7,18,-9  DOT  4)  DOT  x42  DOT  com
Those first two components are not legal host names, and are rejected
by BIND.  But if the browser will automatically do the sum - and I
WOULD NOT use one that would! Too risky! - then you are looking for:


which resolves as Barry has mentioned, above.

Joe Yao				jsdy at - Joseph S. D. Yao
COSPO/OSIS Computer Support					EMT-B
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