Multiple NSs or multiple glue records

[Gustavo Lozano]

Thank you for you answer, but I am looking in how BIND resolver code 
behaves in each case.

I am looking an answer like: If you use multiple NS then BIND will 
try the following NS in the RRset when one fails but if you use 
multiple A record the NS is internally marked as bad when you don't 
get an answer and BIND will not try all IP address.

The example only considers A RRs because I want to center the 
discussion in how the different algorithms that evaluate RTT for each 
NS implemented in BIND8 and BIND9 affect behavior of the resolver.

Thank you.

At 08:10 AM 9/20/2006 +0200, Peter Dambier wrote:
>For diversity both additional AAAA and additional A records are not 
>a good idea.
>
>If server.aaaa does not answer because I do not have IPv6 routing, my resolver
>shall never query server.a1 because it thinks server.* is dead.
>
>Same if server.a1 does not answer because my route works only on a2 it shall
>not even try to reach server.a2
>
>Even if server.a1 and server.a2 are one and the same server I should offer
>them an extra NS until I have some 5 to 13 NS records. With IPv6 or DNSSEC
>it might be enough to have some 8 servers. Then you may think about adding
>A or AAAA records to existing servers.
>
>It is not the quality of your network that is important. Think of somebody
>in Antartica on a shortwave link and heavy thunderstorms. He might succeed
>on the fifth try to your nameservers. That is what I have seen Zimbabwe
>right now. Their nameservers are still working.
>
>Kind regards
>Peter and Karin
>
>
>
>Gustavo Lozano wrote:
> > I think that sometime ago I read a post about what is better multiple
> > NS or multiple A for the same NS. Some of my colleagues and I are
> > having a discussion of what are the pros and cons of the following
> > cases and maybe someone in this list can contribute to our discussion.
> >
> > Case 1.
> > example.com.   IN        NS       a.example.com.
> > example.com.   IN        NS       b.example.com.
> > example.com.   IN        NS       c.example.com.
> > a.example.com IN        A         10.1.1.1
> > b.example.com IN        A         10.2.1.1
> > c.example.com IN        A         10.3.1.1
> >
> > Case 2.
> > example.com.   IN        NS       a.example.com.
> > a.example.com IN        A         10.1.1.1
> > a.example.com IN        A         10.2.1.1
> > a.example.com IN        A         10.3.1.1
> >
> > Thank you.
> >
> >
> > Gustavo Lozano
> >
> >
>
>
>--
>Peter and Karin Dambier
>Cesidian Root - Radice Cesidiana
>Graeffstrasse 14
>D-64646 Heppenheim
>+49(6252)671-788 (Telekom)
>+49(179)108-3978 (O2 Genion)
>+49(6252)750-308 (VoIP: sipgate.de)
>mail: peter at peter-dambier.de
>mail: peter at echnaton.serveftp.com
>http://iason.site.voila.fr/
>https://sourceforge.net/projects/iason/


gus