I have created a GCP compute engine on default vpc, allowing all ports. In the IP range, I have mentioned the external IP address of the compute engine. I was able to ssh to the host via cloudshell gcloud.
Later after 2 days, I was unable to SSH to the host and running into an error - "We are unable to connect to the VM on port 22". So I created a new firewall rule as per the doc https://cloud.google.com/compute/docs/troubleshooting/troubleshooting-ssh-errors and was able to ssh to host successfully.
gcloud compute firewall-rules create firewall_name --allow tcp:22
Question: The initial firewall already has 'Protocols and ports' as 'all' (pls see the above image). Then why I was unable to ssh until I created another firewall rule with explicit mention of port 22?
Update: removed the screenshot per comment. I'm trying to connect from my mac laptop (chrome), connecting to GCP console, ssh via cloud shell (also tried ssh via web option).
turns out, devops admin has revoked gcloud ssh access to everyone citing - gcloud shell gets a seperate IP which is outside of IAP so please use your local terminal or just click on ssh through webconsole