August 2020

Things I just realized I’ve mostly forgotten about: Linux Networking

Trying to get two VPNs working together on the same Ubuntu system was a (relatively short) journey. I still know all the basics and whatnot, but I used to have all of the ifconfig commands memorized. Adding a default gateway, for example, used to be a common task for me back in the “old-school” days of being a Linux sysadmin. I had that command memorized. I knew how to read a route table! The move to Docker containers and AWS has rotted my brain. It’s also a testament to Docker that its networking Just Works in most cases. It’s also scary because running Docker on a system is dangerous since it, by default, modifies iptables to expose ports to the world (0.0.0.0). I wonder what other scary Docker things I’m missing as a result of forgetting how Linux Networking works.

This week, I have started an AWS Architect course and a Linux Networking course.

I am also trying out “A Cloud Guru” since it comes with labs. It’s also very expensive. I noticed that one of the courses in the AWS certification path are super old, but so far it hasn’t mattered too much. It’s still something to worry about–and I’m still within the free-trial period.

Tasks for this week: review networking basics, know how to read a routing table, know how to read a firewall table.

P.S., I remember having to swap a static IP address from one baremetal server to another baremetal server with absolutely 0 downtime using rinetd, I think. That was spooky. I don’t remember the details anymore, but I still remember the fear too well. How is it possible to forget these things?!