DNSBL - How does it work

[olluz]

Heya,

I'm trying understand how DNSBL queries work so that I can improve the configuration and get better results.

Let's say I have multiple DNSBL sites (20 sites).

Will they all be queried in parallel or only a limited number ?
If it's a limited number, will only the first be queried or will the sites be chosen randomly ?
How does the scoring work (if I don't add multipliers). If I set my DNSBL Threshold to "4", does that mean that 5 out of my 20 DNSBL sites need to return something like " true" so that it gets rejected and if only 3 sites have the IP listed it will not be rejected ?

Thanks in advance.

 

[keeka]

AIUI all specified DNSBLs are queried. There's no random/round-robin arrangement though queries might be run in parallel.
Your understanding of the default multiplier is correct, each site will have weight 1.
20 DNBLs seems excessive!