[TEST] Hard to sync new block due to many invalid block Header and DB Not Found Error

[marco-sundsk]

Describe the bug or test When some nodes are running with old genesis file and old code, others are running with new genesis and new code, log will show many info about receive invalid block Header and .Error processing sync blocks due to DB Not Found Error.

Although it seems correct according to chain runtime logic, but it consumes nodes resource, let node confused about peer which should or should not to connect, and stucked at some height waiting downloading some block header.

My suggestion is,

• using some kind of version number to distinguish different code, prevent node with different code version from establishing p2p connections as early as possible to save node resource.
• using some kind of genesis hash or other info to distinguish those node which using different genesis file, prevent node with different genesis file from establishing p2p connections as early as possible to save node resource.

How to Reproduce Steps to reproduce the behavior:

1. As a genesis validator which use a new genesis file and new codes.

Expected behavior OR Outcome of test Node can only establish p2p connection with node which has same code and same genesis.

Specs (please complete the following information):

• OS: Ubuntu 18.04
  • Which cloud / on-premise: AliYun
  • CPU: Intel(R) Xeon(R) Platinum 8163 CPU @ 2.50GHz
  • RAM: 4G
  • Disk space: 500G SSD

Additional context log shows: V/11 4/1/40 peers ⬇ 0.8kiB/s ⬆ 0.7kiB/s 0.00 bps 0 gas/s CPU: 0%, Mem: 304.1 MiB [2019-11-20T03:08:33Z ERROR near_client::client_actor] Error processing sync blocks: Old Block Cause: Unknown Backtrace: [2019-11-20T03:08:33Z WARN near_client::client_actor] Banning node for sending invalid block headers [2019-11-20T03:08:39Z INFO near_client::info] # 55752 Downloading headers 74% V/11 4/1/40 peers ⬇ 0.8kiB/s ⬆ 0.7kiB/s 0.00 bps 0 gas/s CPU: 1%, Mem: 304.1 MiB [2019-11-20T03:08:48Z ERROR near_client::client_actor] Error processing sync blocks: Old Block Cause: Unknown Backtrace: [2019-11-20T03:08:48Z WARN near_client::client_actor] Banning node for sending invalid block headers

Screenshots Optional If applicable, add screenshots to help explain your problem.

[bowenwang1996]

We do use genesis hash to distinguish between nodes. Two nodes with two different genesis hash cannot connect to each other. However, we do want to allow two different client with different code to talk to each other. For as long as neither of them is malicious, they should be able to communicate with each other.