Our company is growing and I had to take down a DHCP scope one of my networks is on and add a new one. Scopes look like this:

  • Old Scope:
  • New Scope:

This was part of a network reorganization due to our growth and this network needed to move scopes. I built the new scope and and activated it and deactivated the old one. I changed the static addresses on our DNS servers and checked the DHCP is working. Now I restarted the 2 DCs that have DNS and DHCP and those records have updated in DNS. All the other computers that rely on DHCP for addresses are either not getting an address or are getting an address but the DNS records are not changing. Do I need to delete the old DNS records for the new ones to show up? Or is it supposed to be updating the DNS record?

DHCP settings for DNS shows:

  • Enabled DNS Dynamic updates according to the settings below (Checked)
  • Always dynamically update DNS records (Checked)
  • Discard A and PTR records when lease is delete (Checked)

Some of the reservation machines get the address but when you check the machine they show DOMAIN (Unauthenticated). Is this also a DNS issue?

  • Your old scope and your new scope are the same size. How did this fix your growth issue? – joeqwerty Sep 18 '20 at 13:28
  • @joeqwerty sorry I had to fix the addresses. They needed to expand and had me move the new one to – JukEboX Sep 18 '20 at 14:23
  • It's peculiar how you move from an RFC1918 ("private") address space to public IP address space (owned by Hewlett Packard) in the process of resolving this growth issue? – Håkan Lindqvist Sep 19 '20 at 17:10
  • @HåkanLindqvist these are all offline networks. Addresses can be pretty much anything. – JukEboX Sep 21 '20 at 11:13

After doing some experimenting I found that the DHCP Refresh was at a week. I also turned on scavenging to clean up the old records. I set the refresh to 8 hours to keep things up to date. I am made sure the top level DNS server was able to reference addresses to the child domains so they can pass DNS queries to them.

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