Herding Packets

It’s been a while since I’ve gotten a blog post up, but with my CCIE recertification out of the way I’m hoping to ramp some volume back up. We’re talking about some sexy stuff today… Ping sweeps! First off, let’s cover why you’d need to sweep up your pings. Some people use the ping sweep as a means to “find” hosts on the network. The problem with this is, devices with host-based firewalls active may not respond to an ICMP ping. If you’re pinging from off the local subnet, there are other reasons you might not get a response back as well, like a host having a mis-programmed default gateway or subnet mask, or an interface ACL on the routing device. That said, ping sweeps are still incredibly useful for helping to find vacant IP addresses on a LAN. Or, at least, IP addresses that are not currently active. Always consult your properly maintained IP documentation to find IPs you can safely use for new deployments (yes, I’m laughing at that one too…).