I didn't understand, please explain clear

#1

On host01 , if we have an entry for app01 in /etc/hosts file like 172.168.238.12 app01 and the DNS server which is used by host01 has 172.168.239.10 as app01's IP then which IP host01 will pick for app01 as per priority.

#2

Hi @Thulasiram

The /etc/hosts file is a local configuration file that maps hostnames to IP addresses. The operating system’s name resolution mechanism first consults it before querying external DNS servers.

Hope this helps!

#3

could you please solve the question in step by step

#4

Priority is controlled by a line in /etc/nsswitch.conf like this

hosts:          files dns
  • hosts is the line concerning DNS loookup
  • files means the file /etc/hosts
  • dns means use the configured DNS server.

In the above example it is configured to look first in the hosts file, and if the entry is not there, then use DNS server. If the order is dns files then it will use DNS server first. That is all there is to it.