clarify NS_FAIL_LIMIT / NS_RR_LIMIT, tunables, and limit proactive lookups?

[Jeremy C. Reed]

I was looking at new code for lib/dns/resolver.c
https://github.com/isc-projects/bind9/commit/27f868f34c79cca80a1c3fd46353258be26c3a7f

The notes xml says: "Fetches for missing name server address records are 
limited to 4 for any domain."

This doesn't seem to match what the new code comments, commit message, 
or what the code does. I may be reading wrong. Can you please explain 
this or clarify this?

Also is there any plan on making NS_FAIL_LIMIT or NS_RR_LIMIT a tunable?

Any discussion or plan to add a configuration option to limit how many 
NS are looked up simultaneously? In other words, if set to 1, don't look 
up address for next NS unless first fails. I used "recursive-clients 1;" 
which did delay the fetches but still did more than one. (I think this 
would be like fetches-per-zone but not about the target domain.)


Jeremy C. Reed

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 tr "noqruvxzabcefg" "abdehikmnoprst"