1. Make deeper analysis of this network service(s) including dependences. What autoruns show? Go up to the thread level for affected process and show here results 2. Give more information on the logs - system, DNS, application and security. Any increase of traffic? 3. See and correct DNS aging and scavenging (http://technet.microsoft.com/en-us/library/cc759204(WS.10).aspx ) 4. Is this long term problem, or it appeared after something (installation, change of configuration, update,...)

I’m using Windows 2003 Server standard SP 2 found problem svchost.exe run service DHCP Client [DHCP] and DNS Client [DNScache] use memory a lot around 2 GB. Try scan virus did not found when to restart service memory is returned. I have 4 servers with the same problem.