Determining Your IP Address
When Linux is installed, the ethernet device is called eth0
For wireless interface it will be called wlan0
The ifconfig command.
[root@ibm ~]# ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:80:48:38:C6:14
inet addr:192.168.0.11 Bcast:192.168.0.255 Mask:255.255.255.0
Finding the interrupts associated with /proc/interrupts
file to get a listing of all the interrupt IRQs used by the system.
[root@ibm ~]# cat /proc/interrupts
CPU0 0: 419048047 XT-PIC timer 1: 144347 XT-PIC i8042 2: 0 XT-PIC cascade 3: 443514 XT-PIC Intel ICH 5: 0 XT-PIC i915@pci:0000:00:02.0 8: 3 XT-PIC rtc 9: 12726117 XT-PIC uhci_hcd 10: 0 XT-PIC acpi, uhci_hcd, eth0 11: 3216 XT-PIC ehci_hcd, uhci_hcd 12: 66 XT-PIC i8042 14: 1320937 XT-PIC libata 15: 18 XT-PIC ide1
NMI: 0 ERR: 0
Changing Your IP Address:
[root@ibm ~]# ifconfig eth0 10.0.0.1 netmask 255.255.255.0 up
[root@ibm sysconfig]# ll /etc/sysconfig/network
-rw-r--r-- 1 root root 48 Nov 27 05:12 /etc/sysconfig/network
The configuraton file can be found at /etc/sysconfig/network-scripts directory.
Interface eth0 has a file called ifcfg-eth0, eth1 uses ifcfg-eth1, and so on.
[root@ibm ~]# cd /etc/sysconfig/network-scripts
[root@ibm network-scripts]# ls -l
total 316 -rw-r--r-- 3 root root 122 Nov 27 05:14 ifcfg-eth0 -rw-r--r-- 3 root root 162 Sep 26 10:45 ifcfg-eth0:1
Using the startup and stop script/commands the ifdown and ifup commands:
[root@ibm ~]# which ifdown /sbin/ifdown
[root@ibm ~]# which ifup /sbin/ifup
Using the command ifup and if down
[root@ibm ~]# ifdown eth0 [root@ibm ~]# ifup eth0
Configuring the DNS server to use:
/etc/resolve.conf
Creating multiple IP addresses associated with a single NIC.
IP aliasing is one of the most common ways of creating multiple IP addresses associated with a single NIC.
[root@ibm ~]# ifconfig eth0:0 192.168.1.99 netmask 255.255.255.0 up
We have to create a /etc/sysconfig/network-scripts/ifcfg-eth0:0 file
DEVICE=eth0:0 ONBOOT=yes BOOTPROTO=static IPADDR=192.168.1.11 NETMASK=255.255.255.0
Configuring the default gateway:
[root@ibm ~]# route add default gw 192.168.1.1 eth0
Updating the /etc/sysconfig/network file to reflect the change.
NETWORKING=yes HOSTNAME=ibm GATEWAY=192.168.0.1
Checking the current routing table
[trinity@ibm ~]$ netstat -nr
Adding Routes using the file /etc/sysconfig/network-scripts/route-eth0
File /etc/sysconfig/network-scripts/route-eth0
192.168.0.0/24 via 192.168.0.1
Checking network card status and speed etc..
mii-tool - view, manipulate media-independent interface status
[root@ibm ~]# mii-tool -v
eth0: negotiated 100baseTx-FD, link ok
product info: vendor 00:00:00, model 0 rev 0 basic mode: autonegotiation enabled basic status: autonegotiation complete, link ok capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD link partner: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
Another Tool.
The ethtool command
ethtool - Display or change ethernet card settings
[root@ibm ~]# ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Advertised auto-negotiation: Yes Speed: 100Mb/s Duplex: Full Port: MII PHYAD: 32 Transceiver: internal Auto-negotiation: on Supports Wake-on: pumbg Wake-on: d Current message level: 0x00000007 (7) Link detected: yes