Here are the particulars (all Windows):

DNS - Our DNS only stores one A-Record per hostname. Scavenging is not currently enabled.

DHCP - DHCP is configured (server level) to perform DNS registration for all clients that configure through DHCP, whether the client requested it or not. 8 day leases.

Workstations - Workstations can have multiple DHCP records in the following scenarios - wired (1), undock and go wireless (2) and/or connect in another vlan (3+).

My main question is how does DHCP/DNS decide which record will be THE record for a hostname? I have seen inconsistent behavior, in that sometimes switching to wireless will make the wireless IP the DNS answer (suggesting a new DHCP record overwrites DNS), but have also seen when moving a machine that the new DHCP entry does not update DNS, leaving the machine with it's old DNS answer, and so unreachable by hostname (suggesting new DHCP entries do not update DNS). Is there an authoritative answer on how DHCP/DNS handles these multiple entries?

My second question, although out of my control to implement, would be can DNS in this type of environment support multiple A-records - is that simply a configuration change?

Thank you!!

  • "DNS - Our DNS only stores one A-Record per hostname" - How do you enforce that? DNS is capable of storing many A records for a single hostname. – Ryan Ries Jul 11 '13 at 13:19
  • if you are seeing multiple records for a single host then an issue you maybe having is that the clients are not releasing their dhcp lease, typcially happens with portables in a dock\undock situation. – tony roth Jul 11 '13 at 13:41

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