I have a small and simple UDP server that's been working in several hosting places for years.
I just created a new vm in the google cloud, a Compute Engine, with linux.
Default settings for a small machine (f1-micro (1 vCPU, 0.6 GB memory) CPU platform Intel Sandy Bridge), with only changes:
- static public IP
- inbound firewall rule to allow UDP traffic at the server port (22000)
Everything works great and can be connected from anywhere in the world, except from the machine itself (there's a stats module that asks the server for info - this also work from remote, but not from the machine itself). This worked in all other linux machines I tried the server on.
I was pointed at changing the address the server binds to as a possible solution, and as I have access to the source code I tried all I can imagine to no effect (binding to 127.0.0.1, 0.0.0.0, "localhost", specific IP...).
I have also tried adding a specific inbound and outbound firewall rules.
There are tons of information around about how to fix when you cannot connect from outside - my problem is the opposite, and I'm of ideas.
Ping etc work normally.
Thanks in advance