We’ve all been there. You make a simple configuration change that should have no impact on production traffic. Suddenly your phone begins to ring, or worse, you lose access to the equipment you were working on.
Here are some common mistakes network engineers make on Cisco gear that cause unexpected outages.
- Forget the add command when adding a vlan to a trunk port.
- Run no ip access list
on a Cisco Router like you would on an ASA firewall.
- Issue a global spanning tree command instead of an interface specific command.
- Apply an untested ACL on the interface you use to manage the router.
- Click OK on an ASDM dialogue box without reading and understanding the impact.
- Delete the current flash image from disk without changing the boot command.
- Issue the debug all command.
- Typo the subnet on a static route when you’re redistributing static.
- Forget to cancel the reload in command.
If you’ve worked on Cisco networks for any length of time, you’ve probably made one of these mistakes or been in the proximity of another engineer who has made one of them. If not, I’m not sure you qualify as a network engineer.
If you can relate to these simple outage-inducing errors, join Jordan Martin, Phil Gervasi, and me as we launch a new live-stream video roundtable called the Network Collective. In our first episode, we’ll hear about some stomach-churning outages caused by each of our guests and lessons learned from those experiences. The live stream begins on April 11th at 7 pm ET. Watch live and comment on Twitter with the hashtag #NetworkCollective. If you can’t watch live, shows will be available in video and audio format.