Assign IP Address and Gateway in Linux from Command Line

if config command is used to assign the ip address to a lan card from the command or from the terminal.

Syntax :

 # ifconfig [-v] [-a] [-s]  [interface]

Options :

• -a :    display all interfaces which are currently available, even if down
• -s :    display a short list (like netstat -i)
• -v :   be more verbose for some error conditions

interface : The name of the interface.  This is usually a driver name followed by a unit number, for example eth0 for  the  first Ethernet interface. If your kernel supports alias interfaces, you can specify them with eth0:0 for the first alias of eth0. One can use them to assign a second address. To delete an alias interface use ifconfig eth0:0 down.

Grub Re-install for SUSE Linux

The below steps can be used to fix un-bootable SUSE Linux OS due to Grub corruption or any damage to GRUB boot loader.

Boot to the SLED or SLES 11 DVD (the SP1 DVD is also fine), select "Rescue System" and login as root.  At the command line enter "grub" and follow this example:

******************
linux:~ # grub

    GNU GRUB  version 0.97  (640K lower / 3072K upper memory)
 [ Minimal BASH-like line editing is supported.  For the first word, TAB
   lists possible command completions.  Anywhere else TAB lists the possible
   completions of a device/filename. ]

grub> find /boot/grub/stage1
 (hd0,0)

grub> root (hd0,0)
 Filesystem type is reiserfs, partition type 0xfd

grub> setup (hd0)
 Checking if "/boot/grub/stage1" exists... yes
 Checking if "/boot/grub/stage2" exists... yes
 Checking if "/boot/grub/reiserfs_stage1_5" exists... yes
 Running "embed /boot/grub/reiserfs_stage1_5 (hd0)"...  18 sectors are embedded.
succeeded
 Running "install /boot/grub/stage1 (hd0) (hd0)1+18 p (hd0,0)/boot/grub/stage2 /boot/
grub/menu.lst"... succeeded
Done.

grub> quit
******************

In this example the root partition is (hd0,0) as returned by the "find /boot/grub/stage1" command.  Use the correct root partition for your system as indicated by this command for the two commands that follow the first one.

Reboot the system and GRUB should come up appropriately.

This Doc is for SUSE Linux Enterprise Server 11 or SUSE Linux Enterprise Desktop 11 but it should work for all SLES and OpenSUSE editons with little and obvious modifications. 

Network Bonding / NIC Teaming in Linux

Network Bonding :- NIC teaming or network bonding is nothing but combining or aggregating multiple network connections in parallel. This is done to increase throughput, and to provide redundancy in case one of the links fails or Ethernet card fails. The Linux kernel comes with the bounding driver for aggregating multiple network interfaces into a single logical interface called bond0.

Bonding is nothing but Linux kernel feature that allows to aggregate multiple like interfaces (such as eth0, eth1) into a single virtual link such as bond0. The idea is pretty simple get higher data rates and as well as link failover. Steps To Configure Bonding in Linux

Step #1: Create a Bond0 Configuration File:

CentOS stores network configuration in /etc/sysconfig/network-scripts/ directory. First, we need to create a bond0 config file as follows:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0
Append the following lines:

DEVICE=bond0
IPADDR=192.168.1.20
NETWORK=192.168.1.0
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes

You need to replace IP address with your actual setup. Save and close the file.