Configuring DNS

Scenarios

Procedure

1. Log in to the ECS as user root.
2. Run the vi /etc/resolv.conf command to edit the /etc/resolv.conf file. Add the DNS server IP address above the existing nameserver information. See Figure 1.

   Figure 1 Configuring DNS

   
   

   The format is as follows:

   nameserver DNS server IP address
   
   

3. Press Esc, input :wq, and press Enter to save the changes and exit the vi editor.
4. Run the following command to check whether the IP address is successfully added:

   cat /etc/resolv.conf

5. Run the following command to check whether an IP address can be resolved from the file system domain name:

   nslookup File system domain name

   Note

   Obtain the file system domain name from the file system mount point.

6. (Optional) In a network environment that uses the DHCP server, edit the /etc/resolv.conf file to prevent the file from being automatically modified upon an ECS restart, and prevent the DNS server IP address added in 2 from being reset.
   1. Run the following command to lock the file:
      chattr +i /etc/resolv.conf

      Note

      Run the chattr -i /etc/resolv.conf command to unlock the file if needed.

   2. Run the following command to check whether the editing is successful:

      lsattr /etc/resolv.conf

      If the information shown in Figure 2 is displayed, the file is locked.

      Figure 2 A locked file