Project Impeteus

For local development it's typical to use /etc/hosts to use custom hostnames for projects. Typically it takes a less than 10 milliseconds for the OS to resolve the etc-host entries.

However on macOS/OSX it can take mulitple seconds to resolve certain hostnames specifically ones containing either .local or .dev in the TLD. This repo exists to help diagnose this issue, raise awarness of it, and suggests some simple workarounds.

Running the tests

Requirements

Homebrew

Running the tests

Assuming you are using Homebrew you can clone and test pretty easily. If you use Homebrew'd Apache 2.4 for active development you should double-check the source first, but it's simply:

./setup.sh # run once
./test.sh

Findings

You can check the detailed results but the important findings are:

• typically macOS resolves /etc/hosts entries in a less than 10ms
• macOS Sierra has a 5s look-up for .dev and .local entries in /etc/hosts
• El Captain has a 5s look-up for .local
• in both cases adding a word between the ip and the hostname like 127.0.0.1 arbitrary test.local cuts that 5s back down to milliseconds

In other words 127.0.0.1 test.local is slow:

$ cat /etc/hosts

127.0.0.1   localhost
255.255.255.255   broadcasthost
::1             localhost

127.0.0.1 test.local

$ curl -w '@curl-template.txt' -s http://test.local -o /dev/null

     time_namelookup:  5.003
        time_connect:  5.004
    time_pretransfer:  5.004
  time_starttransfer:  5.004
          ------------------
          time_total:  5.005

but 127.0.0.1 arbitrary test.local is fast:

$ cat /etc/hosts

127.0.0.1   localhost
255.255.255.255   broadcasthost
::1             localhost

127.0.0.1 arbitrary test.local

$ curl -w '@curl-template.txt' -s http://test.local -o /dev/null

     time_namelookup:  0.006
        time_connect:  0.000
    time_pretransfer:  0.000
  time_starttransfer:  0.000
          ------------------
          time_total:  0.006

Bonjour and .local

It's a known issue that .local See: https://support.apple.com/en-us/HT203136

Why .dev in Sierra?

What's up with the workaround?

man hosts says:

For each host a single line should be present with the following information: IP_address canonical_hostname [aliases...]

Seemingly .dev and .local are less responsive as canonical-hostnames than as aliases?

Other workarounds

• https://coderwall.com/p/ylchfq/osx-yosemite-bonjour-mdnsresponder-problems
• https://www.bram.us/2011/12/12/mamp-pro-slow-name-resolving-with-local-vhosts-in-lion-fix/