Saturday, January 30, 2010

Ubuntu - Overview of Networking

Networks connect computers so that the different systems can share information. For users and system administrators, Unix systems have traditionally provided a set of simple but valuable network services that let you check whether systems are running, refer to files residing on remote systems, communicate via electronic mail, and so on.

For most commands to work over a network, one system must be continuously running a server process in the background, silently waiting to handle the user’s request. This kind of process is called a daemon. Common examples, on which you rely for the most basic functions of your Linux system, are named (which translates between numeric IP addresses and more human-readable alphanumeric names), cupsd (which sends documents to a printer, possibly over a network). Most Unix networking commands are based on Internet protocols, standardized ways of communicating across a network on hierarchical layers. The protocols range from addressing and packet routing at a relatively low layer to finding users and executing user commands at a higher layer.

The basic user commands that most systems support over Internet protocols are generally called TCP/IP commands, named after the two most common protocols. You can use all of these commands to communicate with other Unix systems in addition to Linux systems. Many can also be used to communicate with non- Unix systems, almost all systems support TCP/IP.

This section also covers NFS and NIS—which allow for transparent file and information sharing across networks—and sendmail.

TCP/IP Administration
arp Manipulate address resolution protocol tables.
dig Query domain nameservers.
ftpd Server for file transfers.
host Print host and zone information.
ip Network configuration tool with Cisco IOS-like syntax. Replaces ifconfig, route, and
arp on some systems.
ifconfig Configure network interface parameters.
named Translate between domain names and IP addresses.
netstat Print network status.
ping Check that a remote host is online and responding.
pppd Create PPP serial connection.
quagga Routing daemon.
rdate Notify time server that date has changed.
route Manage routing tables.
routed Dynamically keep routing tables up to date.
slattach Attach serial lines as network interfaces.
sshd Server for secure shell connections.
tcpdump Write network packet information to screen or file.
telnetd Server for Telnet sessions from remote hosts.
tftpd Server for restricted set of file transfers.
zebra Routing daemon.

NFS and NIS Administration
domainname Set or display name of current NIS domain.
makedbm Rebuild NIS databases.
rpcbind DARPA port to RPC program number mapper.
portmap The old name for rpcbind.
rpcinfo Report RPC information.
ypbind Connect to NIS server.
ypcat Print values in NIS database.
ypinit Build new NIS databases.
ypmatch Print value of one or more NIS keys.
yppasswd Change user password in NIS database.
yppasswdd Update NIS database in response to yppasswd.
yppoll Determine version of NIS map at NIS server.
yppush Propagate NIS map.
ypserv NIS server daemon.
ypset Point ypbind at a specific server.
yptest Check NIS configuration.
ypwhich Display name of NIS server or map master.
ypxfr Transfer NIS database from server to local host.

Source of Information : OReilly Linux in a Nutshell 6th Edition

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