Is there a way to change the 5 minute idle timer for NFSv3 mounts?

Issue

• After five minutes of no activity for a NFSv3 share mounted over TCP, the TCP connection is torn-down.
• With certain versions of Red Hat Enterprise Linux, we see the NFS client re-use an existing TCP port.
• This TCP port-reuse behavior sometimes conflicts with stateful firewalls and other network appliances between the NFS client and the NFS server.