CODEWITHSUNDEEP
portgoogle-cloud-platformfirewall
Lyniker Aoyagui
Lyniker Aoyagui

Reputation: 65

Google Cloud Platform Firewall Rules PORT

i´m trying to open some ports in order to be able to run an server-client application inside google Cloud Platform.

Weird fact:

I can open port 7770 and 7771 (ports my application demands) but others like 7772 i cannot even though i made the same config for all.

Ps. I tried to make config into the WEB GUI and also gcloud commands, but I got the same result.

Can anybody help me?

Google Port Information Good Result

Problem

Upvotes: 0

Views: 572

Answers (1)

Kevin
Kevin

Reputation: 1130

You configuration looks correct - I would rather suspect that you have no listener on port 7772, and this is why your open port tester reports the port as closed.

Without changing your configuration - test port 7772 with your open port tester, then port 7773. The test for port 7772 should report that it is closed more quickly than the test for port 7773 [ this is because port 7772 immediately returns RST in response to SYN, because there is no listener, whereas the firewall silently drops SYNs to port 7773 with no response ]

Alternatively, install tcpdump (sudo apt-get update && sudo apt-get install -y tcpdump), then run 'sudo tcpdump -Sttttni eth0 port 7772 or port 7773' just before testing whether the ports are open. For port 7772, you should see SYNs coming from the website, and RSTs in response. For port 7773, you should see nothing at all - but the website will also report this port as closed.

Upvotes: 1

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