How to add DNS servers on an HP-UX server

September 8, 2018

To enable name resolution, you need to configure your HP-UX system to use DNS servers. Once it will be enabled then all the configured name resolutions will be done through the DNS Server.

  • If you will try to nslookup for onlinesbi.com without configuring the DNS then it will read the domain from /etc/hosts file and give the below result: 
    # nslookup onlinesbi.com
Name Server:  ns1.indianrail.gov.in
Address:  203.176.113.82

Trying DNS
Non-authoritative answer:
Name:    onlinesbi.com
Address:  223.31.160.61
  • If the information in /etc/hosts will not be available then it will give the below result: 
    # nslookup onlinesbi.com
Name Server:  ns1.indianrail.gov.in
Address:  203.176.113.82

Trying DNS
looking up FILES
Non-authoritative answer:
Name:    onlinesbi.com
Address:  223.31.160.61

Here I have shown how to add a DNS server on an HP-UX server

Configuration of /etc/resolv.conf

resolv.conf is the name of a computer file used in various operating systems to configure the system’s Domain Name System (DNS) resolver. The file is a plain-text file usually created by the network administrator or by applications that manage the configuration tasks of the system.

  • Log in as a super/root user on the server.
  • Edit the /etc/resolv.conf file and if the file is not available then create it. 
    # vi /etc/resolv.conf
  • Add the DNS servers as nameservers in the /etc/resolv.conf file, as shown below. Here we have added the two DNS servers 203.176.113.82 and 203.176.113.84. After adding the server details, save the file. 
    .
.
search onlinesbi.com www.onlinesbi.com merchant.onlinesbi.com sbiepay.com www.sbiepay.com
nameserver 203.176.113.82
nameserver 203.176.113.84
nameserver 127.0.0.1
.
.

Configuration of /etc/nsswitch.conf

The Name Service Switch (NSS) is a facility in Unix-like operating systems that provides a variety of sources for common configuration databases and name resolution mechanisms. These sources include local operating system files (such as /etc/passwd, /etc/group, and /etc/hosts), the Domain Name System (DNS), the Network Information Service (NIS), and LDAP.

  • Log in as a super/root user on the server.
  • Edit the /etc/nsswitch.conf file, as shown below 
    # vi /etc/nsswitch.conf
  • Add the DNS corresponding to the files which you need to resolve through DNS. Here I configured the resolution of hosts name only through DNS. Save the file. 
    .
.
passwd:       files
group:        files
hosts:        dns files
.
.

Name resolution through DNS Server

  • You have added the DNS server on this machine now all the hosts name resolutions will be done through the DNS servers.
  • nslookup for onlinesbi.com, resolved by DNS server 203.176.113.82 
    # nslookup onlinesbi.com
Name Server:  ns1.indianrail.gov.in
Address:  203.176.113.82

Trying DNS
Non-authoritative answer:
Name:    onlinesbi.com
Address:  223.31.160.61

Note: I have done the above configuration on an HP-UX 11.31 machine.

Last Updated: September 08, 2018

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