dotted hostname is bad IMO

Barry Margolin barmar at
Tue Feb 1 07:56:46 UTC 2011

In article <mailman.1600.1296530179.555.bind-users at>,
 pyh at wrote:

> given the domain name of "", and given an A RR in its zone is: 
> s1.s2.s3  IN  A 
> OK when a dns cache query for the first time, it will 
> follow the logic: 
> #1, has NS RR in cache? (no)
> #2, has NS RR in cache? (no)
> #3, has NS RR in cache? (no)
> #4, has NS RR in cache? (yes most time, since is a famous 
> domain).
> #5, Goto's NS fetch the result. 
> The process is complicated.
> But if the hostname is "", what will the dns cache do by 
> the first query? it will just do: 
> #1, has NS RR in cache? (yes)
> #2, go there fetching the reqult. 
> It's much simple and fast. 
> So I dont think dotted hostname is good pratical.

I don't think it's something you need to worry about.  DNS servers 
organize their cache data structures to make steps 1-4 easy to perform 
all at once.

Time to pull out your copy of Knuth "Sorting and Searching".

Barry Margolin, barmar at
Arlington, MA
*** PLEASE don't copy me on replies, I'll read them in the group ***

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