To mitigate IPv4 exhaustion, IPv6 provides expanded address space, and NAT allows a single public IPv4 address to suffice for many devices assigned private IPv4 address space. Even though NAT has greatly extended the shelf-life of IPv4, some networks need more private IPv4 space than what is officially allocated by IANA due to their size and/or network management practices. Some of these networks resort to using squat space, a term the network operations community uses for large public IPv4 address blocks allocated to organizations but historically never announced to the Internet. While squatting of IP addresses is an open secret, it introduces ethical, legal, and technical problems. In this work we examine billions of traceroutes to identify thousands of organizations squatting. We examine how they are using it and what happened when the US Department of Defense suddenly started announcing what had traditionally been squat space. In addition to shining light on a dirty secret of operational practices, our paper shows that squatting distorts common Internet measurement methodologies, which we argue have to be re-examined to account for squat space.

为了缓解 IPv4 耗尽，IPv6 提供了扩展的地址空间，NAT 允许单个公共 IPv4 地址满足许多分配了私有 IPv4 地址空间的设备。尽管 NAT 大大延长了 IPv4 的保质期，但由于其规模和/或网络管理实践，一些网络需要比 IANA 正式分配的更多的私有 IPv4 空间。其中一些网络诉诸于使用深蹲空间，网络运营社区使用的一个术语，用于分配给组织的大型公共 IPv4 地址块，但历史上从未向 Internet 公布。虽然抢注 IP 地址是公开的秘密，但它会带来道德、法律和技术问题。在这项工作中，我们检查了数十亿条跟踪路由，以识别数千个抢注组织。我们研究了他们是如何使用它的，以及当美国国防部突然开始宣布传统上是深蹲空间时发生了什么。除了揭示操作实践的肮脏秘密外，我们的论文还表明，占位扭曲了常见的互联网测量方法，我们认为必须重新检查这些方法以解释占位空间。