We recently changed IP addresses at a site. When user logs in or when I do an ipconfig /release /renew they get the correct DNS settings from DHCP but after a few minutes it reverts to the old DNS servers addresses. The IP address doesn't change on the workstation or gateway just the DNS. We inherited this network so suggestions on where I can look for old DNS records would be appreciated. We have a Cisco Catalyst 4948 Core switch and this is trunked to HP Procurve 2610 switch. Using Widows 2012 server for DHCP.