Wildcard DNS records

[Carsten Strotmann]

Hello Stefano,

Chiesa, Stefano <Stefano.Chiesa at nttdata.com> writes:

> Hello all.
> I manage several BIND 9.10.4-P8 servers with more of less 600 DNS zones.
> Anyway I never used wildcard DNS record and I hope you can help me to understand.
>
> The need is:
> * I have a dns zone i.e. example.com
> * this zone will have an unknown number of sub domains, let's say siteA.example.com, siteB.example.com, siteC.example.com with other record inside
>
> I need to know if it is possible create an A record valid for all the sub domains, WWW for instance.
>
> I thought that a record like this:
> www.* IN A 1.2.3.4
>
> could work and if I'd query www.siteA.example.com it would return 1.2.3.4 ... but it does not work.
>
> Can you tell me if it is possible and how?

I've did a webinar for Men & Mice a while ago explaining DNS wildcards
and their limits. Video and Slides are online:
<https://www.menandmice.com/resources/webinar-dns-wildcards-demystified/>

Slides:
<https://de.slideshare.net/MenandMice/dns-wildcards-webinar-april-2014>

> I thought that a record like this:
> www.* IN A 1.2.3.4

DNS Wildcards only work on the leftmost label, not "inside" a domain
name.

See also RFC 4592 for a good discussion on DNS wildcards.

Best regards

Carsten