dnsbl-2.uceprotect.net
This is uceprotect.net's secondary level zone. Allocations less than /26 will be automatically be removed if no additional abuse is detected. Allocations of /25 will be allowed to expire only if there are less than two IP addresses listed in the level one blacklist.
A /24 range will expire if four or less IP addresses remain in Level one.
useprotect.net uses a formula for all further delisting calculations within the level two zone:
(Netmask - 1) = Abuser IP's + (Abuser IP's at Netzmask + 1)
For example, a /23 network range will be removed when nine or less IP addresses remain, a /22 network range will be removed if fourteen or less IP addresses remain, and a /21 network range will be removed if twenty-four or less IP addresses remain.
Furthermore, in order for a network range to be removed from a level two listing, that IP address must have already been removed from a level one listing.
Level two listings can usually only be removed at the request of your upstream service provider.
dnsbl-3.uceprotect.net
This is uceprotect.net's third level zone. If after all the above listings in level two and level one have been worked out, and a level three listing still remains, the best you can do is complain to the ASN for which spam continues to come from, or take your business elsewhere. There is nothing an end server administrator can do to influence uceprotect.net's level three blacklist zone.