Pre/Post Azure Migration DNS changes

Jason Johnson 1 Reputation point
2022-08-15T15:36:27.68+00:00

I am doing a lift-and-shift migration for a client with ~30 servers.

My question is...

The current address space in my client's on-prem environment is 192.168.0.0/16 we are migrating the machines to a 10.0.0.0/16 address space.

What is the strategy and method for name resolution after migration?

Do I create DNS A records in the source DC's before I do the migration?

I have the option to use Azure Active Directory Domain Services...should I also use Azure Private DNS and create the LDAP SRV record there?

I need to make this migration as seamless as possible for the end users who use the servers everyday.

As you can tell I am having a bit of a problem with wrapping my head around this issue.

Any help and guidance would be appreciated.

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  1. JimmySalian-2011 41,916 Reputation points
    2022-08-16T20:46:14.46+00:00

    Hi Jason,

    There are couple of options with you on this migration and I will list down each:

    1. Option - Simple - During the cutover you can create a new DNS Record or Update the existing records in the DNS to point it to the new IP address and this can be either Onpremise DNS or if you are planning to provision Azure AD Domain Services as this will be sync with your Onpremise AD.Update production DNS entries for source servers to point to the new IP address in short that is 10.x.x.x address.
    2. Option 2 - Complex - Use Azure DNS private Resolver and detailed information is over here dns-private-resolver-overview, you do not need to create Azure AD Domain Services for this.

    Note the TTL value of the DNS records should be less before the cutover so the clients refresh/resolve with the new entries and correctly resolve the address after the cutover.

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  2. JimmySalian-2011 41,916 Reputation points
    2022-08-24T21:51:29.11+00:00

    @Jason Johnson ,

    Just checking if the answer was helpful and --please don't forget to upvote and Accept as answer if the reply is helpful--

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  3. Vineet Kumar Gupta 161 Reputation points
    2022-10-27T11:26:08.317+00:00

    If the there us already connectivity between 192.168.0.0/16 to a 10.0.0.0/16 address space. Then after migration need to update the forward lookup and reverse lookup IPs in DNS server directly or need to run the ipconfig /registerDNS from the server and hit restart from azure portal .

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