Intermittently, numerous PCs with Windows 7 stop resolving DNS for a site (no specific site -www.wyff4.com
today). When this happens the browser displays a server not found error. Using command prompt, cannot ping the name (could not find host). Use NSLOOKUP www.wyff4.com
and an IP address is returned. Able to ping the IP address or type IP in browser and get to site. Able to ping or browse to other sites by name. Using Wireshark no DNS entries show up. If DNS cache is flushed or the DNSClient service is disabled it starts functioning. 3000 node network. Have been looking for solution several days.