RBL performance: caching nameserver vs RBL mirroring

[Alex Neuman van der Hans]

Michael Masse wrote:
> Can someone explain the pro's and con's of each with respect to
> performance and accuracy, or am I confused and they are not actually
> mutually exclusive, and have nothing to do with eachother?
> 
> Mike
> 
Caching nameserver means "keep a copy of DNS lookups so I don't have to 
do it again for some time". RBL Mirroring means "don't ask a remote RBL 
every time I get a message; download the changes to the list periodically".