Should bind ignore bad cached NS?

Cricket Liu cricket at
Wed Nov 17 21:13:07 UTC 1999

> Here's what I think is what's I've been seeing as far as a "troubling"
> difference between 8.2.2 and 4.9.7. One domain which exibits this
> effect is ''
> Anyway, the NSs in the DNS records are bogus:
>     23h33m37s IN NS
>     23h33m37s IN NS
> No A records are returned or exist for those names.
> Now I _think_ what's going on once BIND gets that NS info, it
> ignores the NS entries in the 'Nic DNS records. So if I now do a
> 'dig mx' BIND will try to contact one of
> the above 2 NS servers and will fail. According to 'Nic,
> the DNS servers for that domain are: SERVER0.DATACOM.NET and
> then all is well.
> It appears that 4.9.7 would ignore any cached NS entries for a
> domain, and use the 'Nic records...

Right, because the intrazone NS RRs have higher credibility than the
ones in the com zone.

> Can anyone else reproduce this?

This "deadlock" scenario has been described by Mark Andrews on
bind-users before.


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