In Inetcfg/protocols/Tcp-Ip/ - Default IP Address. Should that be or should it be the default IP address of the server?

We changed our ip addresses here on our 2 server cluster and I dont ever
remember that having anything but in there.

But after the IP change, BM was blocking our backups on our cluster
vols. After I put in the IP address of the private Nic of the server
there our backups started working again.

Does anyone now why or if you should have your default ip of your private
nic in that setting above. Or maybe explain why it needs it now.