Thank you for your question and reaching out.
I can understand you are having query related to DFS Name space DNS settings.
Please note that DFS is tightly integrated with Active directory ,so its configurations as well.
You can create CNAME record of your OLD DFS-2 server to point to DFS-1 server. and it should be worked.
But I would suggest you to consider only for temporary purpose until your completely get rid of DFS-2.
Hope this answers your question :)
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