Recursive lookups

[EpcH]

Hi All again,

I searched the forum before submitting my question since I couldnt find any clear answer to my following question.

When I run a test at www.dnsstuff.com, I get a warning as :

Took off 2 points since ns1.xxxxxxxx.net allows recursive lookups (if lots of people are using the server, it can slow down).

Took off 2 points since ns2.xxxxxx.net allows recursive lookups (if lots of people are using the server, it can slow down).

Can anybody tell me how can I disable recursive lookups on Plesk ?

And if I disable them, is there any trade of involved ?

Thanks all.