Check the sync is working with closed inbound

[sridharmeganathan]

Verify that the node can sync while the inbound wsPort is closed.

Scenarios to check:

1. Node can sync from genesis
2. Node can sync after reaching the max network height

[jondubois]

I tested the scenarios on devnet (running only v2.3 nodes).

I verified the first sync scenario by running the node on localhost with a fresh database and connecting to devnet. The node was able to sync from scratch.

To verify the second scenario, I ssh'ed into a node on devnet which was already at a good height. I also watched the HTTP API endpoint /api/blocks to monitor the current height and checked that it was receiving blocks passively from the network. Then I blocked the inbound wsPort (port 5000) using firewall rules on Digital Ocean.

• The logs indicated that the node was still synching.
• The node height continued to increment every 10 seconds.
• Opening the port allowed the node to exit sync mode and return to receiving blocks passively.