FreeBSD +NFS + mail services

[Francisco Reyes]

Looking for any links/comments/info on performance settings for a FreeBSD 
mail setup using NFS.

In particular how does the client decides how many client nfs programs to 
run? I noticed that 2 machines today were both using 22 client 
connections each. Is that a hard limit in the FreeBSD nfs client?

Although I have found several NFS related info articles.. nothing particular 
to FreeBSD.. specially in an ISP type of setup.

The Oreilly NFS+NIS book was primarly Solaris focused so that was not of 
much help.

Our current NFS server is a 5.4 machine and a new one coming online soon 
will be 6.X stable. Client machines are 5.4

Any sysctl variable that would be of help to change?