DNS mess duplicate entries with different IP

Posted on 2007-10-02
Last Modified: 2011-09-20
Have a customer with two sites with one DC/DNS server on each site.

Laptop pc's are switching sites on a daily basis. There are lots of duplicate entries where a pc have two or three different ip adresses on the same site. And some ip adresses are listed with two or three different PC-names.

How do I clean up this mess?

I know you guys need more information from me. Just ask for it.
Question by:TANGLAD
    LVL 70

    Accepted Solution

    You need to enable aging and scavenginig of DNS and set the non-reresh and refresh periods to low values - (1 day?). If you are using DHCP you also should reduce the lease period to the same value.

    LVL 1

    Author Comment

    Thanks for the links.

    If the users are switching sites on a daily basis, then how do I best setup the DCHP lease periods and DNS scavenging?

    and what happens if a pc's is on one site on the start of the day and then travels to the other site later that day?
    LVL 70

    Expert Comment

    You need to balance the lease renewal period - too short and you will get lots of renewals (not necessarily a problem), but too long and leases will not be released (more of a potential problem). You could start by opting for a 4hr lease and see how it goes. The the normal advice then would be to set ageing and scavenging to match.
    LVL 1

    Author Comment

    Ok you say a 4 hr lease in DHCP

    And then a 4 hr DNS no-refresh interval

    And how about the DNS refresh interval?
    LVL 1

    Expert Comment

    We had a situation where the dhcp lease period was set to 8hrs and someone set the no refresh interval and refresh interval to 8 this caused lots of issues wheer dns entries were deleted. Prod systems went down and caused alot of problems.

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