How long do I need to wait to be safe?

[wchull]

Leading up to this week we decided to change the names of our external DNS Name Servers. Neither the Servers hosting our external DNS's nor the public addresses were changing but due to a re-branding of our company name we wanted to change the names from NS1.oldcompanyname.com to NS1.newcompanyname.com.

To accomplish this switch over we added Host (A) records for the new servers in the new DNS zone and then added NS records to all DNS zones that we host externally. In other words we went from 2 NS records per zone to 2 (i.e 2 old records and 2 new records). Once we had everything in place we contacted our domain registration company and had them register our new names on the internet.

All went well but we still have 4 NS records in all of our DNS zones and I would like to know the following:

1. When is it safe to remove the NS record for the old name?

2. When can I remove the Host (A) records for these server from the old zone?

 

[Cstorms]

With my hosts NS registration takes 4-8 hours however there is a warning in there somewhere about a delay from 48-72 hours for it to fully propagate to the other servers receiving updates on NS records. As long as your primary and secondary servers are fully replicated with the new zone data you should be save to get rid of your old NS records. Are these actually new servers or same servers with different zone names?

 

[wchull]

These are the same physical servers. They just have different public names.

 

[dtrtel]

There are two separate issues to consider.

The first is TLD domain server propogation (root servers)
as Cstorm points out. This is from the change in
Registration of the domain. Can vary widely by TLD
(ie 4hrs to 72 hours)

The other issue has to to with resolver cache
which depends on your refresh and retry timers in your
SOA record. It also depends on whether the resolvers
in the machines querying the nameservers behave and
use the timers. There were still some win98 clients
that had problems with this, but that was ancient times
in Internet years.

--jeff

http://linkedin.com/in/JeffLynch