| Lesson 2 | Tools for network configuration and maintenance |
| Objective | Describe the function of netstat, arp, and ifconfig. |
Tools for Network Configuration and Maintenance
Network troubleshooting is one of the most challenging tasks you need to perform. You must fix problems involving your own computer,
as well as how it interacts with computers around the world. Luckily, you have several tools at your disposal to find the information you need:
ping, netstat, arp, and ifconfig.
ping Command
The ping command checks network connections between computers by sending small test packets of information to a remote host.
The "pinged" computer returns a copy of the test message to check for accuracy. For example, a modem connection with a noisy line will cause information loss that will be reported by ping. Use the ping command when you need to check the existence and integrity of a network connection.
netstat Command
netstat displays information about every TCP/IP interface on your computer. It can also display your routing table and interface statistics.
When you need detailed information on your computer's interface(s) to the network, use netstat.
ARP
The Address Resolution Protocol
(ARP)[1] determines which host's network interface is assigned to an IP address, and allows your network's hardware to properly format data for the destination network device. The
arp command displays and modifies these associations. You will use it to track down IP-to-Ethernet mapping problems.
ifconfig
ifconfig displays and modifies interface parameters such as IP address and netmask.
When you find you need to modify interface parameters, use ifconfig.
| Tool | Function | When used |
ping | Checks network connections between computers | To check the existence and integrity of network connections |
netstat | Displays information about every TCP/IP interface Displays your routing table and interface statistics |
To get detailed information on your computer's interface(s) to the network |
arp | Displays and modifies associations between host network interfaces (Ethernet devices) and IP addresses | To track down IP-to-Ethernet mapping problems |
ifconfig | Displays and modifies interface parameters | To modify parameters such as IP address and netmask |
Redhat Utilities Functions
Before moving on to the next lesson, click the Exercise link below to practice matching configuration and connection tools with their functions.
Matching Utilities with their functions
netstat:Displays TCP/IP interface information, interface statistics, and routing tablesarp:Sets and displays information binding host interfaces to IP addressesifconfig:Configures and displays interface parameters such as IP address and netmaskping:Tests network connections and their quality by sending small test packets over the network
The netstat -r command provides the same output as the /sbin/route command.
Support for device Identification using WWIDs during installation
Fibre Channel and Serial Attached SCSI (SAS) devices can be now specified by a World Wide Name (WWN) or a World Wide Identifier (WWID) for unattended installations. WWN is part of the IEEE standard which makes it easier to identify storage devices during installation for users utilizing Storage Area Networks (SAN) and other advanced network topologies. When a storage device is attached to a server using multiple physical paths for redundancy or improved performance, WWN for any of these paths is sufficient to identify the device.
Initial RAM disk File for Legacy Hardware
The initial RAM disk file on 64-bit PowerPC and 64-bit IBM POWER Series systems is now named initrd.img. In previous releases, it was named ramdisk.image.gz. Static IPv6 address support for network installation In Red Hat Enterprise Linux 6.2, a static IPv6 address can be specified for the ipv6 boot option for network installations. In the next lesson, you will learn how to manage network interfaces with ifup/ifdown.
[1] ARP: The Address Resolution Protocol. ARP is the method Ethernet computers use to assign IP addresses to Ethernet card addresses.
