It is a program(svchost.exe) used to "host" certain services in Windows that run from dll's. Since it is asking you will probably have to accept it in ZA. It hosts several services depending on what you have enabled on your
system, so you may have to block specific ports with ZA if you are asked by ZA to allow access "from" the internet and you are running services(servers) that use it that you do not want accessed from the internet. This is one of
those thing that Zonelabs should be documenting because it is confusing to anyone without an in-depth understanding of windows and is something that
affects most(if not all) users of ZA.