On Mon, 6 Jun 2005 [EMAIL PROTECTED] wrote:
> David Brodbeck wrote:
> > Loren Wilton wrote:
> >> You'ld think that there should be some way to do a reverse DNS to
> >> determine from an ip the domains that exist on that ip. I suspect
> >> though that the whole internet fabric is designed the other way
> >> around, and that this information is probably something that no
> >> single registrar would know.
> >
> > In theory, a reverse lookup could give you all the hostnames
> > associated with that IP. In reality, almost no one actually sets up
> > multiple reverse DNS records for such sites. So yes, it's difficult.
>
> Maybe a "reverse SPF" record is called for...
>
> _spf.0.0.10.in-addr.arp TXT "example.org, some.example.com"...
>
Two-fold problem with either of those solutions:
1) It would depend upon the spammer actually registering and keeping
accurate that kind of data. (Do you really think that they'll want
to give the farm away ;).
2) The size of DNS answers would quickly get large enough to cause
technical problems. DNS normally uses UDP packets to keep overhead
low (one small packet for query, another for the response). As soon
as you get more than about 500~1000 bytes of data in an answer you'll
have to switch to TCP if you want to get the full data. (A lot more
load on the DNS servers and more network overhead. ;(
--
Dave Funk University of Iowa
<dbfunk (at) engineering.uiowa.edu> College of Engineering
319/335-5751 FAX: 319/384-0549 1256 Seamans Center
Sys_admin/Postmaster/cell_admin Iowa City, IA 52242-1527
#include <std_disclaimer.h>
Better is not better, 'standard' is better. B{
