[dnsdist] dnsdist-cache-questions

Tom lists at verreckte-cheib.ch
Tue Sep 22 09:26:51 UTC 2020

I'm new on dnsdist (1.5.0) and have some questions:

1) I've created a simple cache-configuration (more or less copied from 
the manual) like this:

packetcache = newPacketCache(10000, {maxTTL=86400, minTTL=0, 
temporaryFailureTTL=60, staleTTL=60, dontAge=false})

The backend server is "up" and joined in the pool "bind":
 > showPools()
Name                                    Cache         ServerPolicy Servers
bind                                  6/10000     leastOutstanding 

When I now want to query the cache via console, I always get the 
following error:
 > getPool("bind"):getCache()
Command returned an object we can't print: Trying to cast a lua variable 
from "userdata" to 

Any hints for this?

My 2nd question:
Assuming the dnsdist-cache is working, has a A-Record-cache-entry for 
"www.example.com" and dnsdist is in front of a resolver and the resolver 
(backend) stops working. dnsdist has the record "www.example.com" still 
in his cache, because only the backend server stops working. Why does 
dnsdist not answer the query for "www.example.com" from the cache, when 
the backend server is "down"? Is there a configuration option for this?

Many thanks.
Kind regards,

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