I have a Windows NFS server and several CentOS linux servers which were mounting volumes from it.  The Windows server moved to a new network and even though DNS works and the NFS mount was mounted by hostname, it appears the NFS client also makes note of the ipaddr value, which is no longer valid.  This causes the typical hanging mounts, df, issues one would expect.  How do I resolve this retroactively?
How to resolve when the IP of a NFS server changes
ip;nfs;unmounting