Mattias Geniar shares multiple ways of writing IP addresses. One of them is with optional zeros, so
127.0.0.1 is the same as
Most of us write our IP addresses the way we've been taught, a long time ago: 127.0.0.1, 10.0.2.1, ... but that gets boring after a while, doesn't it? Luckily, there's a couple of ways to write an IP address, so you can mess with coworkers, clients or use it as a security measure to bypass certain (input) filters.
Read There’s more than one way to write an IP address on ma.ttias.be.