If you change the filer IP you will have to set it using the following cli.
dfm host set <filerid-or-name> hostPrimaryAddress=<new-ip-address>
If you have changed the host name also use the following cli.
dfm host rename <oldname> <new name>
To check if connectivity from DFM server to filer is working fine use the dfm host diag < filer id>
Regards
adai