NFS, the Network File System has three important characteristics:
I'll say something on both issues in this HOWTO. Please make sure you read the security section of this HOWTO, and you will be vulnerable to fewer silly security risks. The passages about security will at times be pretty technical and require some knowledge about IP networking and the terms used. If you don't recognize the terms you can either go back and check the networking HOWTO, wing it, or get a book about TCP/IP network administration to familiarize yourself with TCP/IP. That's a good idea anyway if you're administrating UNIX/Linux machines. A very good book on the subject is TCP/IP Network Administration by Craig Hunt, published by O'Reilly & Associates, Inc. And after you've read it and understood it you'll have higher value on the job market, you can't loose ;-)
There are two sections to help you troubleshoot NFS, called Mount Checklist and FAQs. Please refer to them if something dosn't work as advertized.