I have a VSphere installation hosting two Windows Server 2008 R2 installations. One of them is a complete install that serves as a DHCP server and that I use for administration. The other install is a Server Core install that serves as Domain Controller and DNS server.
While the DHCP install always responds to ping, as does the VSphere, the DNS server stops regularly responding to ping and doesn't start working back until I run arp -d to clean the ARP table.
What could be causing this problem?