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I made a DNS change a few hours ago and I just ran the following command with the following output:

nslookup mydomain.com ns1.mynameserver.com
Server:  ns1.mynameserver.com
Address:  111.111.111.111

Name:    mydomain.com
Addresses:  222.222.222.222
      333.333.333.333

222.222.222.222 is old IP. 333.333.333.333 is the new IP address. Why are they both showing up? Since I'm querying the authoritative DNS server directly, shouldn't only the new IP address be shown?

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First, check the zone file on the master (or the configuration if it was built through a control panel or the like). Make sure the old address was deleted. Check the zone file on the server. Check the server's logs. –  David Schwartz Jun 7 '12 at 20:55
    
@DavidSchwartz Our DNS is done by an internal group of admins so I dont have access to the zone files or configuration. I am asking because I think they maybe neglected to remove the old IP address but I want to understand more before I accuse anyone of botching the job. –  Jeff Jun 7 '12 at 21:38
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Can't you politely ask them to investigate without having to do any accusing? Then they can secretly fix the problem and claim that everything looks fine to them. –  David Schwartz Jun 7 '12 at 22:21
    
@DavidSchwartz I can, and I did. Unfortunately, it has been easier and more reliable to deal with SF then it was to deal with the IT admins today. –  Jeff Jun 7 '12 at 22:33
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1 Answer 1

up vote 7 down vote accepted

Neglecting to remove the old address is exactly what happened. It's not something that would occur when the old record is still in cache when the new one is added or something like that - a different new answer always fully replaced an old answer for a RR in a cache.

There's a record for the old address somewhere in the zone file, and a record for the new address somewhere in there, too. There are several valid syntax methods by which the record can be defined in the zone - it could be easy to overlook if they weren't specifically looking for the record to remove.

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Thanks. I didn't even know it was possible to have 2 records pointing to different places. –  Jeff Jun 7 '12 at 23:05
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