For the purposes of doing web development, I have several domain names specified in my `/etc/hosts`. These represent several different websites that are being run locally.

```
127.0.0.1    site1.local
127.0.0.1    site2.local
127.0.0.1    site3.local

```

This works fine, but I'm seeing a 5 second delay in loading pages from any of these domains. Browser developer tools attribute this delay to DNS, and it's always exactly 5 seconds.

Curiously, this also only happens in Chrome and in Firefox. Safari has no delay at all.

I thought that perhaps the browser is querying the normal DNS servers before falling back to the hosts file. Doing a DNS query with `dig site1.local` returns no results (as you would expect), but also returns results very quickly (17ms), so that doesn't seem to be the case.

What is causing the 5 second delay in looking up hosts in the `/etc/hosts` file, and how do I reduce or eliminate this delay?