Troubleshooting networking issues in docker and kubernetes is often difficult and the root cause can be in different places including the underlying networking infrastructure. I have collected some information which might be helpful.
Some commands you also might find useful when working with kubectl
Packet filtering is essential for network security and Linux offers this out of the box. There are different possibilities like iptables, nftables or firewalld, and a basic understanding of these is very useful.
Last Wednesday I was attending the DevOps Connect: DevSecOps at RSAC 2021, whereas a cool project was presented: Crowdsec, a collaborative behavior detection engine, coupled with a global IP reputation network
Ever since I discovered Cloudflare I am a big fan of it. They offer a lot of great products, especially also for me as an individual with a very tiny - or non-existent - IT budget.