Aktifkan DNS di CentOS

Setelah instalasi CentOS 5.8 selesai, ternyata PC belum bisa konek ke Internet. Padahal di sisi router, IP dan MAC address yang digunakan oleh PC ini sudah didaftarkan di router Mikrotik. Agar setiap kali mengakses Internet tidak perlu melakukan otentikasi lagi. Langkah selanjutnya adalah meng-edit 2 file, yaitu /etc/sysconfig/network-scripts/ifcfg-eth0 dan /etc/resolv.conf.


Isi file /etc/sysconfig/network-scripts/ifcfg-eth0 sebelum di-edit :
# Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+
DEVICE=eth0
IPADDR=192.168.17.12
BROADCAST=192.168.17.255
NETMASK=255.255.255.0
BOOTPROTO=static
#BOOTPROTO=dhcp
HWADDR=00:10:DC:CD:A0:39
ONBOOT=yes
#DHCP_HOSTNAME=localhost.localdomain

Isi file /etc/sysconfig/network-scripts/ifcfg-eth0 setelah di-edit (tambahkan GATEWAY):

# Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+
DEVICE=eth0
IPADDR=192.168.17.12
BROADCAST=192.168.17.255
NETMASK=255.255.255.0
GATEWAY=192.168.17.1
BOOTPROTO=static
#BOOTPROTO=dhcp
HWADDR=00:10:DC:CD:A0:39
ONBOOT=yes
#DHCP_HOSTNAME=localhost.localdomain

Isi file /etc/resolv.conf adalah kosong. Selanjutnya edit menjadi
nameserver 192.168.17.1

Testing sebelum konfigurasi DNS
[root@localhost ~]# ping www.yahoo.com
ping: unknown host www.yahoo.com

Testing setelah konfigurasi DNS
[root@localhost ~]# ping www.yahoo.com
PING ds-sg-fp3.wg1.b.yahoo.com (106.10.139.246) 56(84) bytes of data.
64 bytes from ir1.fp.vip.sg3.yahoo.com (106.10.139.246): icmp_seq=1 ttl=52 time=19.5 ms
64 bytes from ir1.fp.vip.sg3.yahoo.com (106.10.139.246): icmp_seq=2 ttl=52 time=22.3 ms

--- ds-sg-fp3.wg1.b.yahoo.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 2038ms
rtt min/avg/max/mdev = 19.594/20.979/22.364/1.385 ms