How do I get my nodes to find each other on macOS?

Question

When I run Alice and Bob validators:

./target/release/polkadot --alice --validator --base-path /tmp/relay/alice --chain chainspec-raw.json --port 30333 --ws-port 9944

./target/release/polkadot --bob --validator --base-path /tmp/relay/bob --chain chainspec-raw.json --port 30334 --ws-port 9945

They cannot find each other and no blocks are produced.

However, if I run the second validator node (Bob) specifying the bootnode of Alice like so:

./target/release/polkadot --bob --validator --base-path /tmp/relay/bob --chain chainspec-raw.json --bootnodes /ip4/127.0.0.1/tcp/30333/p2p/12D3KooWP2XSK96JraZ5PxK6uC33ae8fMRfmugP5DtuwxhrbGPUH --port 30334 --ws-port 9945

then it works and blocks are produced and finalized.

Why aren't the nodes finding each other via peer discovery?

I am on macOS.

Answer 1

My firewall was blocking the peer discovery.

System Preferences > Security & Privacy > Firewall

This was my setup:

This means my nodes will not be able to auto-discover because incoming connections are blocked (I would have to specify the bootnodes manually).

Unchecking "Block all incoming connections" and checking "Enable stealth mode":

Then re-running the Alice and Bob validators, I get this pop-up to approve incoming connections:

This will add "polkadot" to the approved list of software:

And finally Bob will find Alice.

Note: I ended up opting for leaving the "Block all incoming connections" checked and manually specifying the bootnode as this sufficed for my node testing and allowed me to keep a more secure configuration for my firewall.