Before you can use NFS, be it as server or client, you must make sure your kernel has NFS support compiled in. Newer kernels have a simple interface on the proc filesystem for this, the /proc/filesystems file, which you can display using cat:
$ cat /proc/filesystems minix ext2 msdos nodev proc nodev nfs
If nfs is missing from this list, you have to compile your own kernel with NFS enabled, or perhaps you will need to load the kernel module if your NFS support was compiled as a module. Configuring the kernel network options is explained in the “Kernel Configuration” section of Chapter 3.