Can't open port 8080 on Google Compute Engine running Debian

Does your network have the corresponding firewall rule? Follow the next steps to create it.

1. Go to the Developers Console and click on the corresponding project.

2. Click on 'Compute'

3. Click on 'Networks'

4. Click on the name of the corresponding network. You can see in which network is your instance clicking on 'VM instances' under the 'Compute Engine' section or with the command:

   gcloud compute instances describe <instance> | grep "network:" | awk -F/ '{print $(NF)}'

5. Under the Firewall rules section, click 'Create new'

6. Enter a name for the firewall rule and in the field 'Protocols & ports' type: tcp:8080

7. Save the rule

After that, you should be able to access your HTTP server.

Otherwise you can try to see if your machine receives the SYN TCP packets in that port with the command: sudo tcpdump -i eth0 port 8080

Hope it helps

In GCE Web Console > Networks > Firewall rules > edit your RULE, remove TARGET TAGS and apply.

GL