Duplicate DNS entry issue

Posted on 2009-12-21
Last Modified: 2012-05-08
I am going through our DNS zone file and it is a mess.  There are tons of duplicate host entries and for some of the entries I am not certain which ones are actually valid.  What is an easy way to determine which of the entries are actually valid?  The only thing I could think of was dumping DHCP and dumping the zone file, combining them in Excel, sorting, etc.  Is there any easier way?
Question by:rufustmac
    LVL 12

    Accepted Solution

    I would start by turning on scavenging of stale DNS records and shortening your DHCP lease.  Your DNS server probably isn't removing old record so they keep building up.  After making the changes allow a few days for the old records to get removed.
    LVL 57

    Assisted Solution

    Do you have dns scavenging enabled?  If not, you may want to enable it.  Otherwise dumping DHCP and DNS may be the "easiest" way.
    LVL 4

    Expert Comment

    It may be tedious, but you could also just ping each dual entry and see which one works, delete the other one.
    LVL 57

    Expert Comment

    The problem with using ping is that you not only will have the same host name with more than one IP address, you may have the same IP address assigned to more than one host name.  So although the ping will respond, you don't know which host is returning it.

    Author Closing Comment

    We are going to just delete all the dynamic entries, turn the TTL down and turn on scavenging until everything is all cleared up.  Thanks.

    Featured Post

    How your wiki can always stay up-to-date

    Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
    - Increase transparency
    - Onboard new hires faster
    - Access from mobile/offline

    Join & Write a Comment

    Suggested Solutions

    If you have a multi-homed DNS setup in windows, you can have issues with connectivity to the server that hosts the DNS services (or even member servers of your domain if this same DNS server is a DC). This is because windows registers all of its IPs…
    ADCs have gained traction within the last decade, largely due to increased demand for legacy load balancing appliances to handle more advanced application delivery requirements and improve application performance.
    Need more eyes on your posted question? Go ahead and follow the quick steps in this video to learn how to Request Attention to your question. *Log into your Experts Exchange account *Find the question you want to Request Attention for *Go to the e…
    Access reports are powerful and flexible. Learn how to create a query and then a grouped report using the wizard. Modify the report design after the wizard is done to make it look better. There will be another video to explain how to put the final p…

    734 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    20 Experts available now in Live!

    Get 1:1 Help Now