Posting: For a good number of years…

content/blog/2020-01-04-setting-up-a-local-resolver-on-macos/index.md

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+---
+title: Setting up a local resolver on macOS
+date: '2020-01-04T02:30:25+00:00'
+layout: micropost
+categories:
+- web
+- web development
+- dns
+- internet
+---
+
+For a good number of years I was using Basecamp's Pow for local web
+development and one of my favourite features was the in built local DNS
+resolver that meant that `*.dev` would resolve to `127.0.0.1`. This mean
+that I had a unique hostname for every site I was building and running
+locally which I have found incredibly useful.
+
+Unfortunately Pow no longer sees active development (the GitHub repo has
+been archived) so I wanted to see if I could set up the same kind of
+local resolver on my Mac without using it.
+
+It turned out to be pretty straightforward!
+
+Note: We're using `.localhost` instead of `.dev` because Google own the
+`.dev` TLD and in 2017 they added an HSTS rule to Chromium that forces
+any `.dev` domain to use HTTPS. As you can imagine, this is not ideal
+for local development so web developers everywhere had to adjust their
+setups.
+
+First of all we need to install Dnsmasq. This will handle the local name
+resolution. If you're using Homebrew this is dead simple:
+
+    $ brew install dnsmasq
+
+Then we need to configure it to resolve any domain name that ends in
+`.localhost` to resolve to `127.0.0.1`.
+
+Uncomment the following line:
+
+    # /usr/local/etc/dnsmasq.conf
+    conf-dir=/usr/local/etc/dnsmasq.d
+
+Add the following file to the Dnsmasq configuration directory:
+
+    # /usr/local/etc/dnsmasq.d/localhost
+    address=/.localhost/127.0.0.1
+
+Start `dnsmasq` as root (It needs to be running as root to be able to
+bind to port 53):
+
+    $ sudo brew services start dnsmasq
+
+Next we need to tell macOS about the local resolver.
+
+Add the following file (You will need to do this as `root`):
+
+    # /etc/resolver/localhost
+    nameserver 127.0.0.1
+    domain localhost
+    search_order 1
+
+And voila! Any domain ending in `.localhost` should now resolve to
+`127.0.0.1`. We can test this with a ping:
+
+    $ ping foobar.localhost
+    PING foobar.localhost (127.0.0.1): 56 data bytes
+    64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.122 ms
+    64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.262 ms
+    64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.281 ms
+
+## So why is this useful?
+
+That's a very good question! Here's some of the reasons I've found:
+
+1.  If you're developing an app that relies on a number of small
+    services it can be useful to differentiate them by domain.
+2.  It makes OAuth callback URL's more readable.
+3.  It's useful for external services that require a domain name to
+    authenticate. A good example of this is font services such as
+    Typekit or Hoefler & Co.
+4.  It just looks pretty up there in the URL bar!