Piradius.net appears to be up to its dark grey hat antics again with a server at 126.96.36.199 which is providing services to the current run of Zbot trojans, as seen (for example) with this recent ThreatExpert report.
Robtex reports the the server is also being used as the NS for a number of Zbot related domains, notably x2dns.ru, cedns.ru, updata-1.com, admin-systems.com, db-1.net, upd01.net, ssl-updates.net and several others connected with this spam run. 188.8.131.52 is also the download server for various Zbot components.
Although Piradius.net probably has many legitimate customers (primarily from Malaysia, Thailand and South-East Asia), it seems to have a lot of bad ones too (including Yohost.org). Prudent network administrators may want to consider blocking 184.108.40.206 - 220.127.116.11 which will probably not cause too many problems.