You can enable checking of IP addresses for listing in DNSBL. DNSBL (DNS blocklists) are deny lists of domains and IP addresses. DNSBL are usually used to fight against spam and block IP addresses with suspicious activity.
VMmanager checks virtual machine IP addresses for listing in added DNSBLs. The IP address gets the "DNSBL Blocked" status if it appears in at least one list. A blocked IP address cannot be assigned to a virtual machine.
Checking IP addresses for their presence in the DNSBL occurs each time an IP address is released. The frequency of these checks is not adjustable.
DNSBL management
To manage DNSBL, enter Networks → DNSBL.
To add a list, press Add DNSBL and specify the domain name of the list. We recommend using the bl.spamcop.net list.
Press 
to delete the list.