Tap vs Lightning Strike
Earlier this year my lab suffered a near lightning strike. A tree right outside the lab was struck by lightning, causing damage to multiple electronic and electrical devices outside and inside the building. Outside, the lightning disabled an exterior lighting system and my phone lines. Inside, the lightning took a severe toll on the lab. The cable modem to the outside world was destroyed. The NIC on the lab firewall facing the cable modem was fried, along with a second NIC in the firewall. The NIC on a sensor watching a tap between the cable modem and firewall was also destroyed. So far, this is a grim story.
I have one good piece of news to report, and it involves the tap I mentioned sitting between the cable modem and firewall. The tap survived the lightning strike. More precisely, the tap continued to pass traffic even when its monitoring interface was damaged.
Had the tap been receiving traffic from the modem or firewall, it would have continued to pass it. This truly amazed me. Frequently monitoring practitioners worry that inserting a tap in their network architecture will introduce a single point of failure. In my experience, all of the components around the tap are more likely to fail. A well-engineered tap will continue to pass traffic -- perhaps even when struck by lightning!
The tap that survived my lab lightning strike was built by Net Optics. Congratulations to the Net Optics engineering and manufacturing teams for building quality hardware.
Comments
Net Optics does not claim that their taps can survive a lightning strike, tornado, or any other strange act of God.
kthnkx.
/jk
You are a big tap proponent - we get it. But I fail to see this as a reason for or against a tap. There are good and bad reasons to use a tap, a machine acting as a bridge, or a monitor port on a switch. I don't see your experience of the consumer grade cable modem getting blown to bits as relevant to pro's or cons list of any of the options.
Any device that "survives" a lightning strike should be treated with 0 confidence. Just because it still "works", doesn't mean its still working correctly. Take it from someone who worked in a TV/VCR repair shop. There are lots of small components in them that will cause issues that may not manifest themselves immediately. Diodes, Transisters, and IC chips are incredibly notorious for it. And most of these modern devices use flashable PROMS, programable gates, etc that are even more susceptible due to static sensitivity. I'd recommend getting a new one.
I'd recommend at the very least, replace the wall wart that came with it, if not scrapping the device entirely.
Think of it this way: If this had been a production enviornment, with phones ringing off the hook and a bunch of angry users, you wouldn't be sitting there saying "well, it's working, but we should probably replace the A/C adapter that came with it, just in case some flashable EPPROM got scrambled". No, you would just be happy that it was working as you started fixing everything else around it that failed.
sheesh.