OT: Perl Compatible Regular Expressions

[Chris Rees]

On 17 December 2011 20:22, Paul Welsh <paul at welshfamily.com> wrote:
> On 17 December 2011 20:11, Paul Welsh <paul at welshfamily.com> wrote:
>
>> For example, this works fine:
>> *.domain.com
>> - matches mail.domain.com, xxx.mail.com, etc
>
> Just thinking, if it's a domain like amazon.com then perhaps
> *.amazon.com is pretty safe.  After all, I believe Exim does a reverse
> lookup on the IP to retrieve the hostname.

Yes... except *.amazon.com isn't a valid regular expression.  It just
happens to work because the * is ignored.  My earlier suggestion
should fit your requirements.

Chris