In this article, we will introduce one of the most useful tools that every engineer responsible for the network layer should have in their arsenal: VPC flow logs. Back in the day when private data centers were cool, when we needed to troubleshoot network problems, we had to “tap the wire” and that could take many forms such as installing packet sniffers on various network segments or configuring complicated traffic mirroring options. Enter VPC flow logs! With the cloud and the advent of software defined networks, troubleshooting IP networks has never been easier.