A question from RFC 3403
SM
sm at resistor.net
Wed May 27 17:43:19 UTC 2009
At 07:22 26-05-2009, sandoche BALAKRICHENAN wrote:
>An example from RFC 3403
>
>The URN might look like this:
>
> urn:cid:199606121851.1 at bar.example.com
>
> This Application's First Well Known Rule is to extract the characters
> between the first and second colon. For this URN that would be
> 'cid'. The Application also specifies that, in order to build a
> Database-valid Key, the string 'urn.arpa' should be appended to the
> result of the First Well Known Rule. The result is 'cid.urn.arpa'.
> Next, the client queries the DNS for NAPTR records for the domain-
> name 'cid.urn.arpa'. The result is a single record:
>
>cid.urn.arpa. IN NAPTR 100 10 "" ""
>"!^urn:cid:.+@([^\.]+\.)(.*)$!\2!i"
>
>My question is when the application has already converted
>"urn:cid:199606121851.1 at bar.example.com" -> cid.urn.arpa.
>
>==> why does the regexp string again searches for "urn:cid:" ?
Because it's not a terminal lookup.
>REGEXP - A <character-string> containing a substitution expression
>that is applied to the original string
>
>==> Anyone have an idea why it always should be applied to the
>original string?
The answer is in the paragraph that follows the one you quoted.
Regards,
-sm
More information about the bind-users
mailing list