How does hostname resolution work without hosts file?

Question

The company I work at has a lot of local server accessible via hostname (ABCSRVDC01 for example). To connect to one of them over SSH I don't need to use the ip address of the server, but instead use the hostname. Me knowing what hostnames are, goes to check the hosts file for a list of all available servers, but to my surprise, it was empty. Which left me baffled. I was used to putting hostnames in the hosts file to have an easy to remember alias for a specific ip. But it was empty.

So how does my computer know how to resolve ABCSRVDC01 to an actual ip address?

I wish to use this kind of setup in my homelab. I have a PowerDNS installed on one of my servers and use .local pseudo-TLD to access my local services (nexcloud.local, heimdall.local etc.). Now I wish to access the underling server using a hostname.

I cant figure out how are they doing this. They use a local DNS? Some router configuration? Does PowerDNS support resolving hostnames not only FQDN?

score 3 · Answer 1 · answered Jun 14 '19 at 15:15

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I cant figure out how are they doing this. They use a local DNS?

Yes.

answered Jun 14 '19 at 15:15

joeqwerty

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Or Bonjour! https://en.wikipedia.org/wiki/Zero-configuration_networking – ceejayoz Jun 14 '19 at 15:26

score 2 · Accepted Answer · answered Jun 14 '19 at 21:12

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A hostname is a domain name, when combined with a DNS search suffix from your local resolver. On linux this is usually in the /etc/resolv.conf file, or possibly /etc/resolv.conf.d/ directory.

answered Jun 14 '19 at 21:12

Ryan Fisher

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`DNS search suffix` was the key thing I was missing. – CodeBreaker Jun 15 '19 at 08:49

How does hostname resolution work without hosts file?

2 Answers2