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google-cloud-platformvirtual-machine
Jake Schmidt
Jake Schmidt

Reputation: 15

Google cloud virtual instance cannot ping my Mac (checked firewalls)

I have a virtual machine instance running on Google Cloud Compute Engine — a preemptible free-tier CPU running Ubuntu 17.04. The end goal is to connect it to a MongoDB running on my local machine, a 2015 Macbook Pro (OS 10.12.6). But first, I've been trying to ensure the VM can reach my Mac via ping.

I've disabled my Mac's firewall. I've also configured my VM's firewall rules to allow all inbound and outbound traffic, to no avail:

ingress firewall rules, egress firewall rules

How might I get this instance to ping my Mac successfully?

Upvotes: 0

Views: 623

Answers (1)

David
David

Reputation: 9721

Does your Mac's IP address begin with 10., 192.168., or between 172.16. and 172.32.? These are private addresses only reachable within your Mac's local network, which is (part of) why GCE cannot reach your VM.

This is part of a very common configuration. An ISP only allocates one (or a small number) of IP addresses to your home or business. A router on the network performs NAT to share that IP addess between computers on the local network, which instead use private IP addresses for themselves. As the router doesn't know what to do with the inbound MongoDB traffic, it blocks it.

There are two common ways around this that are usually found in your router settings:

  1. "port forwarding" where you tell the traffic to forward all traffic on port 1234 to your Mac. This can get MongoDB working, but not ping.
  2. If you have whole extra IP addresses, "DMZ" where your router directly forwards an entire extra IP to your instance. If you have only one IP address this is not an option as that IP is needed to be shared for other devices on the Wifi.

You likely also have a firewall on the router. If you use a DMZ or port-forwarding you must make sure that firewall allows traffic through too.

That said, I'm not sure that this is a sensible thing to do. Opening up your local network to the internet can create major security issues, plus it is likely unreliable more expensive (free tier only provides 1GB egress/month, your db traffic could exceed this).

Actually running MongoDB on instances within GCE is almost certainly a better option in every regard for you.

Upvotes: 1

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