Heavy Networking 439: When Routine Turn-Ups Turn Evil

We do a bit of troubleshooting on today’s Heavy Networking podcast.
Turning up a new circuit should be easy. Some IP addressing, maybe a routing adjacency to bring up, or perhaps a default route.
Do some pings, run a speed test, check for interface errors, make a few notes in the NMS, and that’s about it. Routine stuff for any network engineer.
Except sometimes it isn’t. What happens when all the normal stuff seems okay, but you’ve got weird connectivity problems? How do you fix that issue?
Our guest is Chris Parker, a network engineer who works for a London ISP, and is also a Juniper Networks ambassador. Chris blogs at Network Fun Times.
He and Ethan start the show talking about certifications, why Chris has earned so many, and his favorite books and blogs that helped him.
Then they walk through an issue that Chris encountered with an SRX firewall, the troubleshooting steps he took and why they didn’t help, and then how a “monitor traffic” command finally provided the clue he needed.
Chris also shares his personal recommendations on troubleshooting:

* More eyes
* Say it out loud
* Trust no one. Trust nothing. Make no assumptions
* Improve your process
* Don’t assume all vendor kit works the same
* Even “RFC-compliant” doesn’t mean it all works the same
* Automation is good because humans suck where robots excel

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Show Links:
Chris Parker on Twitter
Lessons In JunOS Troubleshooting: Fixing A LAN With A Weird Problem – Network Fun Times
“Monitor Traffic” Juniper Documentation – Juniper Networks
Cisco IOS Debug Command Reference – Cisco Systems