I'm attempting to synch Stellar core (v10.0.0) and most of the time, it is behind https://horizon.stellar.org/ by 20 to 100 ledgers.

To make sure it's not just horizon that's lagging, I check the `info` of the Stellar node and, although a little more difficult to get a high-level view, I check the logs.

- `NODE_IS_VALIDATOR` is true 
- `NODE_SEED` is set
- The node has been able to get to the "Synced!" state, but it did not stay there long
- I see a lot of "Dropping peer" and "New connected peer" entries in the log
- It sometimes pauses in `successful handshake with`. For example, as I write this, that has been the latest log entry for 12 minutes

I will update this question as I know what else to add to help people diagnose the problem.