MacOS – Why does `hostname` return “dserodio” and not “dserodio.local”

macosNetwork

When I run hostname it returns dserodio instead of dserodio.local, which causes problems with Python servers.

I can run sudo hostname dserodio.local but I have to set it again after rebooting.

How can I make it the hostname dserodio.local definitively?

Best Answer

I think you need this:

    sudo scutil –-set HostName dserodio.local

The command that you are running is temporary.

Source

http://osxdaily.com/2010/09/06/change-your-mac-hostname-via-terminal/

Related Solutions

MacOS – Why is the hostname resolution taking so long

I was able to fix this issue by explicitly setting the HostName using scutil to be the same value as LocalHostName:

$ scutil --set HostName $(scutil --get LocalHostName)

Now:

$ sudo scutil --set HostName MacBook-Pro
$ time python -c 'import socket; print(socket.getfqdn())'
MacBook-Pro
python -c 'import socket; print(socket.getfqdn())'  0.01s user 0.00s system 86% cpu 0.016 total

I was confused before because of the following:

$ scutil --get LocalHostName
MacBook-Pro

$ hostname
MacBook-Pro.local

But:

$ scutil --get HostName
HostName: not set

MacOS – Device name on router is different than OS X hostname

There are three different hostnames that macOS/OS X uses:

ComputerName
HostName
LocalHostName

Each of these values can be found in /Library/Preferences/SystemConfiguration/preferences.plist

ComputerName

scutil --get ComputerName

This is Apple "friendly" name for the computer and can be found in System Preferences >> Sharing >> Computer Name. According to the man page for scutil, it is described as "The user-friendly name for the system."

According to Apple, the ComputerName is The AppleTalk name and the default name used for SLP/DA¹. It's a zero-configuraiton protocol that allows you to set up a simple network without a DNS/DHCP server but allow you to reach the different resources via a host name.

HostName

scutil --get HostName

According to the scutil man page, the HostName is "the name associated with hostname(1) and gethostname(3)". This name can come from any of the following sources:

The name provided by the DHCP or BootP server for the primary IP address
The first name returned by a reverse DNS (address-to-name) query for the primary IP address
The local hostname
The name “localhost”

(In my virgin install of El Capitan, the HostName defaulted to LocalHostName)

LocalHostName

scutil --get LocalHostName

This is for Bonjour² services on the LAN. This is how, on a small LAN without DNS/DHCP, Apple computers can discover and interact with resources such as file sharing on other machines, printers, etc. This name gets set when you initially configure your Mac.

TL;DR

It is using "the first name you ever set" because during initial setup, it set the LocalHostName which it assumed would forever be. When you re-configured using the GUI, you changed the ComputerName which did not modify the LocalHostName.

If you wish to fix this in your router, simply set your LocalHostName using the command:

scutil --set LocalHostName MyNewComputerName.domain

¹ SLP/DA Service Location Protocol/Directory Agent. The Service Location Protocol is a service discovery protocol that allows computers and other devices to find services in a local area network without prior configuration.

² Bonjour is Apple's implementation of zero-configuration networking, a group of technologies that includes service discovery, address assignment, and hostname resolution.