/etc/hosts - is a hosts file in Ubuntu distribution. The file contains a list of IP addresses and associated hostnames. Each line in hosts file will correspond to one IP address entry followed by associated canonical hostname.
So, every entry would resemble -
Here, IP addresses and canonical hostnames should be separated by at least one blank space. And, if we put # at the beginning of every entry then that particular line would be ignored.
One of the key benefits in keeping important entries in hosts file - it is quite useful in case our DNS servers are not reachable for some reason. In addition to, almost all applications check /etc/hosts file before asking for relevant entries from a DNS server. Therefore, we can utilize this property to our advantage as and when required.
Note: Following operations would require you to have superuser privileges. In case you don't have one, then contact your System Administrator for assistance.
/etc/hosts - hosts file in Ubuntu
A normal user can only read the contents of a /etc/hosts file. We need to have administrative account i.e. root privileges to make necessary changes, if required.
To view the contents of /etc/hosts file using cat command-line utility, issue the following in terminal -
It would return with the following -
127.0.0.1 localhost 127.0.1.1 techpiezo-pc ::1 localhost ip6-localhost ip6-loopback ff02::1 ip6-allnodes ff02::2 ip6-allrouters
127.0.0.1 is for our localhost (needed for IPv4 capable hosts),
127.0.1.1 is a fully qualified domain name (FQDN) of the machine we are working on, and
::1 localhost ip6-localhost ip6-loopback ff02::1 ip6-allnodes ff02::2 ip6-allrouters
it is also for our localhost (needed for IPv6 capable hosts).
Now, to edit the /etc/hosts file - issue the following in terminal -
sudo nano /etc/hosts
replace nano with a text-editor of your own choice.
Append the file and provide the IPv4 address for associated canonical hostname. For instance,
Similarly, replace IPv4 addresses with IPv6 addresses to get desired outcome.
In conclusion, we have discussed /etc/hosts - hosts file in Ubuntu distribution.