When working on your Magento 2 shop it is always a good idea to put it in maintenance mode. The only problem with this approach is that nobody, not even you :), can now work with the store. To bypass the maintenance mode for your IP, simply run the following command from your Magento 2 root directory. This way you can work as normal, all other visitors will get the maintenance mode message.

php bin/magento maintenance:enable --ip="12.345.678.123"

Undo:

php bin/magento maintenance:disable --ip="12.345.678.123"