I used to have a machine sitting around that I would power up whenever I needed to build a new OpenBSD kernel or rebuild the source tree due to a patch or a new version of the OS being released. Eventually I moved that machine into a VirtualBox virtual machine running on my desktop. Recently I moved that VM into VMWare's free ESXi hypervisor running on some pretty decent hardware. It got me wondering how much I could lower compile times by adjusting how many vCPUs were allocated to the VM.
I recently had an issue with an OpenBSD firewall where the number of state table entries was hitting the default limit of 10,000. When this limit is reached, no new state entries can be created. If you're using "keep state", "modulate state" or "synproxy state" on your rules or if you're running OpenBSD 4.1 or newer (where "keep state" is the default on all rules) this could mean that:
- You cannot make new connections through the firewall
- You cannot make new connections to the firewall
- You cannot make new connections from the firewall
So.... if you hit the state table limit it's kinda bad, mmmkay?