is an abbreviation for "DNS whitelist". It is a list of IP addresses that some people may want to treat more favourably.
provides a Whitelist of known legitimate email servers to reduce the chances of false positives while spam filtering.
The purpose of a White list is to specify elements whose inclusion in an e-mail guarantee it will pass the filter and be delivered.
In this list, mail servers of Internet service
providers (ISP) and known email providers (Google, Hotmail, Yahoo) and others
are included. Also payment and software solutions, hosting and domain
providers, other trusted services are in this list.
Every IP that is not known to be a source of abuse itself can be registered at wl.nszones.com.
Registration is with one time fee of 30 Euro.
Purpose of wl.nszones.com is to improve deliverability of legit emails send by registered IP's.
Therfore registered IP's are excluded from blocklists as sbl.nszones.com, dyn.nszones.com and bl.nszones.com.
To prevent that abusers will deliberatley register their IP's with wl.nszones.com we will drop every registered IP from the whitelist
immediatley as soon as any kind of abuse is originating from it.
You can check if your IP address is listed, using our White List Lookup.