ns1.company.com registered to 184.108.40.206
ns2.company.com registered to 220.127.116.11
ns1.company.com updated to 18.104.22.168
ns2.company.com updated to 22.214.171.124
ns3.company.com registered to 126.96.36.199
ns4.company.com registered to 188.8.131.52
In preparation for a migration of all accounts from one box to a new one, I updated the nameserver ips so that old clients who never bothered to change their nameservers to ns3/ns4 would still see the new server.
For a few days, this worked. Tonight, out of seemingly nowhere, I am seeing this behavior:
ns3.company.com shows LINKED and working on 184.108.40.206 but actually going to 220.127.116.11
ns4.company.com shows LINKED and working on 18.104.22.168 but actually going to 22.214.171.124
ns3/ns4 had NEVER been registered to that address before.
For whatever reason, browsers, dig, and nslookup were not seeing the registered nameservers and defaulting to looking up HOST records on the company.com. In DNS, *.company.com was still pointing to 126.96.36.199. Changing *.company.com to 188.8.131.52 now makes the ns3/ns4 operate correctly.
I don't really understand why it happened, but that patch fixed it.