One thing that's been continuously annoying me when doing WordPress development on the go is when something somewhere inside WordPress decides to send requests to external urls when I don't even have Internet connection or it's slow and flaky (tethering, slow Wi-Fi, etc). This results in random lag when loading pages, especially if I haven't opened my dev WordPress instance for a long time.
Turns out there's an easy and undocumented (other than in code) solution. To block external HTTP requests right in WordPress's core itself, open up wp-config.php and add WP_HTTP_BLOCK_EXTERNAL like so:
Whenever this variable is present, external requests will be ignored, unless you specify your own comma-separated whitelist of domains using WP_ACCESSIBLE_HOSTS like so:
define('WP_ACCESSIBLE_HOSTS', 'site1.com, site2.com');
In the meantime, if you found this article useful, feel free to buy me a cup of coffee below.