ns-west.cerf.net has one IP number , which also has a corresponding reverse pointer. srv2-jacobdelafon.ma and omnicommediagroup.net point to the same IP. dhd.com, mlb.com, xif.com, cerf.net, emct.com and at least 100 other hosts use this as a nameserver. cerf.net is a domain controlled by two nameservers at cerf.net themselves. They are on different IP networks. Incoming mail for cerf.net is handled by two mailservers having a total of six IP numbers. There are six duplicated IP numbers. Some of them are on the same IP network. ns-west.cerf.net is hosted on a server in United States.