Re: [sitefinder-tech-discuss] Technical issues encountered by a k12 site

[Andrew Newton <anewton@verisignlabs.com>]

Jeremy,

My response is in-line:

Jeremy_Powell@sbcss.k12.ca.us wrote:

> 1) Our spam filter utilizes an NXDOMAIN response to recognize
> non-existent domains and therefore does not allow mail from
> them.  Some spam is sent this way.  Whois is not an acceptable
> replacement for this because it is massively inaccurate.

I agree that nicname/whois is not the correct solution for your problem. 
 One method this type of check is to compare the result of the forward 
domain query against the result of a query for the wildcard (e.g. if 
example.com == *.com).

> 2) Microsoft name resolution on newer operatin systems goes
> through the stages of file, DNS, NetBIOS.  For a school district
> that has implemented a Windows domain that does not exist in DNS
> and is therefore resolved in the NetBIOS stage, 
> the wildcard causes resolution of names to cease at the
> DNS stage because that stage never returns the expected NXDOMAIN.
> Implementation of a local DNS for the non-existent domain will
> resolve this.

There are two solutions for picking a non-existant name for such 
purposes.  The first is to pick a non-existant name within a domain 
delegation for which you have control (e.g. if you have been delegated 
example.com, then use does-not-exist.example.com).  The second solution 
is to pick a name within the reserved TLD's specified in BCP 32 / RFC 
2606.  These TLD's are .example, .test, .invalid, and .localhost.

-andy