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  1. Introduction
  2. Network Topology
  3. Hardware Connections
  4. TCP/IP Ports and Addresses
  5. Network Protocol Levels
  6. Data Link Layer and IEEE
  7. Network Protocol Categories
  8. Repeaters, Bridges, Routers
  9. ARP and RARP Address Translation
  10. Basic Addressing
  11. IP (Network)
  12. TCP (Transport)
  13. UDP (Transport)
  14. ICMP
  15. Hardware Cabling
  16. Wireless media
  17. Outside Connections
  18. Ethernet
  19. Token Ring
  20. ARCnet
  21. AppleTalk
  22. FDDI
  23. IPX/SPX
  24. NetBEUI
  25. AppleTalk
  26. SNA
  27. Others
  28. Simple Routing
  29. More Complex Routing
  30. IP Masquerading
  31. Firewalls
  32. Domain Name Service (DNS)
  33. Virtual Private Networking
  34. DHCP
  35. BOOTP
  36. RPC and NFS
  37. Broadcasting and Multicasting
  38. IGMP
  39. Dynamic Routing Protocols
  40. Simple Mail Transfer Protocol (SMTP)
  41. Simple Network Management Protocol
  42. Network Services
  43. Installing Drivers
  44. Network Operating Systems
  45. Applications
  46. Wide Area Networks
  47. Backing up the network
  48. Fault Tolerance
  49. Troubleshooting
  50. Commonly used Network Ports
  51. Networking Terms and Definitions
  52. Networking RFCs and Protocols
  53. Further Reading
  54. Credits


Network File System (NFS)

NFS, defined by RFC 1094, is a method for client systems to use a filesystem on a remote host computer. NFS uses the UDP protocol and is supported by RPC.

Remote Procedure Call (RPC)

RPC, defined by RFC 1057, is a set of function calls used by a client program to call functions in a remote server program. The port mapper program is the program used to keep track of which ports programs supporting RPC functions use. The port mappers port is 111. In Redhat Linux the portmapper daemon is started in the /etc/rc.d/init.d/portmap and the daemon program is called "portmap".

The rpcinfo command

The command "rpcinfo -p" will show the port numbers that are assigned to the RPC services.

   program vers proto   port
    100000    2   tcp    111  portmapper
    100000    2   udp    111  portmapper
    100011    1   udp    747  rquotad
    100011    2   udp    747  rquotad
    100005    1   udp    757  mountd
    100005    1   tcp    759  mountd
    100005    2   udp    762  mountd
    100005    2   tcp    764  mountd
    100003    2   udp   2049  nfs

Services that may be listed include:

  • rquotad - Enforces the set quotas for remote mounted NFS systems.
  • mountd - Performs the requested mounts.
  • nfs - Handles the user interface to the kernel module that performs NFS.

NFS related services in Linux include:

  • amd - Runs the automount daemon for automatic remote filesystem mounting such as nfs. It is especially worthwhile for working with removeable media such as floppies or CD ROM disks.
  • autofs - This is the startup, stop, and status script for the automount program used to configure mount points for automatic mounting of file systems.
  • nfs - Provides Network File System server services.
  • netfs - Mounts and unmounts Network Fils System (NFS), Windows (SMB), and Netware (NCP) file systems. The mount command is used to perform this operation and no daemon is run in the background.

The /etc/exports file is used to configure exported filesystems.