OT: Perl Compatible Regular Expressions

[Paul Welsh]

On 18 December 2011 12:00,  Chris Rees <utisoft at gmail.com> wrote:
>
> mail[0-9]*.domain.com should do?
>
> Are you trying to match mail.domain.com too? If you don't want to
> match that, then use + instead of *

Hi Chris

Thanks very much for responding.  Can you just explain what the:
[0-9]*
actually means?

To give some more real world examples, I'd need to match:
mail-01.domain.com, mail-02.domain.com ... mail-15.domain.com
This would take one line in the whitelist file using regular
expressions versus 15 separate IP addresses or FQDNs.

Another real world example:
smtp-out-81-59.amazon.com, smtp-out-81-60.amazon.com, smtp-out-81-61.amazon.com