Software used

• Red Hat 9 (Shrike) Get RH9

Commands used

• ifconfig
• route

Configuration files used

• /etc/sysconfig/network
• /etc/sysconfig/network-scripts/ifcfg-eth0
• /etc/resolv.conf

Step 1 - Configure IP Address, Mask and Gateway

Example: Set 172.30.10.101/24 on eth0. Note that /24 is shorthand for specifying a network mask of 255.255.255.0, then set the default gateway to be 172.30.10.1

Method I - Temporary settings (lasts till next restart)

• [root@frida root]# ifconfig eth0 172.30.10.101 netmask 255.255.255.0 broadcast 172.30.10.255
  [root@frida root]# route add default gw 172.30.10.1
  

Method II - Permanent settings

• [root@frida root]# cat /etc/sysconfig/network
  NETWORKING=yes
  HOSTNAME=frida.localdomain
  GATEWAY=172.30.10.1
  [root@frida root]#
  

• [root@frida root]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
  DEVICE=eth0
  BOOTPROTO=static
  BROADCAST=172.30.10.255
  IPADDR=172.30.10.101
  NETMASK=255.255.255.0
  ONBOOT=yes
  [root@frida root]#
  

• [root@frida root]# service network restart
  Shutting down interface eth0:                              [  OK  ]
  Shutting down loopback interface:                          [  OK  ]
  Setting network parameters:                                [  OK  ]
  Bringing up loopback interface:                            [  OK  ]
  Bringing up interface eth0:                                [  OK  ]
  [root@frida root]#
  

Step 2 - Configure DNS server

• echo “nameserver 207.62.187.54” > /etc/resolv.conf

Step 3 - Verify settings

Show interfaces and routing table

• [root@frida root]# ifconfig
  eth0      Link encap:Ethernet  HWaddr 00:0C:29:7E:C3:EC
            inet addr:172.30.10.101  Bcast:172.30.10.255  Mask:255.255.255.0
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:1586 errors:0 dropped:0 overruns:0 frame:0
            TX packets:1264 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:100
            RX bytes:181119 (176.8 Kb)  TX bytes:193645 (189.1 Kb)
            Interrupt:9 Base address:0x10a4
  
  lo        Link encap:Local Loopback
            inet addr:127.0.0.1  Mask:255.0.0.0
            UP LOOPBACK RUNNING  MTU:16436  Metric:1
            RX packets:454110 errors:0 dropped:0 overruns:0 frame:0
            TX packets:454110 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:0
            RX bytes:31015690 (29.5 Mb)  TX bytes:31015690 (29.5 Mb)
  
  [root@frida root]#
  
  

• [root@frida root]# route -n
  Kernel IP routing table
  Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
  172.30.10.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
  169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0 eth0
  127.0.0.0       0.0.0.0         255.0.0.0       U     0      0        0 lo
  0.0.0.0         172.30.10.1     0.0.0.0         UG    0      0        0 eth0
  [root@frida root]#
  

Ping the gateway (tests IP and mask settings)

• [root@frida root]# ping 172.30.10.1
  PING 172.30.10.1 (172.30.10.1) 56(84) bytes of data.
  64 bytes from 172.30.10.1: icmp_seq=1 ttl=64 time=0.318 ms
  64 bytes from 172.30.10.1: icmp_seq=2 ttl=64 time=0.320 ms
  64 bytes from 172.30.10.1: icmp_seq=3 ttl=64 time=0.638 ms
  
  --- 172.30.10.1 ping statistics ---
  3 packets transmitted, 3 received, 0% packet loss, time 2013ms
  rtt min/avg/max/mdev = 0.318/0.425/0.638/0.151 ms
  [root@frida root]#
  

Ping google (tests DNS and default gateway settings)

• [root@frida root]# ping google.com
  PING google.com (64.233.167.99) 56(84) bytes of data.
  64 bytes from py-in-f99.google.com (64.233.167.99): icmp_seq=1 ttl=246 time=76.5 ms
  64 bytes from py-in-f99.google.com (64.233.167.99): icmp_seq=3 ttl=246 time=75.8 ms
  64 bytes from py-in-f99.google.com (64.233.167.99): icmp_seq=4 ttl=246 time=75.9 ms
  
  --- google.com ping statistics ---
  4 packets transmitted, 3 received, 25% packet loss, time 3051ms
  rtt min/avg/max/mdev = 75.897/76.106/76.507/0.426 ms
  [root@frida root]#