I have a debian NFS server on an internal network, that I want to protect from modification by malicious agents. I want something stronger than per-IP or per-mac firewall rules. The clients are all linux.
From what I have read/skimmed so far, use of kerberos with NFS requires per-user authentication, which in turn requires users log in via the KDC. Some users of the server are mobile, so this is an unappealing option.
I have so far not pursued a VPN as an option, mostly due to the performance implications.
What is the simplest way to achieve the above?
Note, I'm not overly concerned with preventing sniffing of network traffic, only with modification of data.