DwarfPool mining: Blockchain-syncing and firewall settings

Question

Some questions related to this DwarfPool (ETH) mining command:

ethminer -F http://eth-eu.dwarfpool.com/0xb...

Is it correct that...

• ethminer does not download the blockchain, it only creates DAG files.
• When using pool/farm mining as shown, I don't need a geth (or eth) background process that syncs the blockchain.
• So geth is only needed for administration tasks (create/list accounts, show balance etc.) and I can add the --nodiscover and --maxpeers 0 arguments (or other flags?) to disable blockchain syncing.

Regarding firewall settings:

While mining...

• ethminer logs mining actions
• tcpdump -i eth0 -A -s 1500 -n host eth-eu.dwarfpool.com shows connections to Dwarfpool server
• and after some hours (first, I saw only an empty page) https://dwarfpool.com/eth/address?wallet=b... shows charts and statistics

So, mining seems to work. But...

• Do I need to open the ethereum listen port 30303 for proper functioning (e.g. to get payouts)?
• If this is the case: Is it enough to allow connections only to the Dwarfpool server eth-eu.dwarfpool.com?

Thank you

Answer 1

ethminer does not download the blockchain, it only creates DAG files

It does not download the entire block chain but by definition the PoW function is applied over block (and implicitly transaction) headers meaning it needs to download at least a block that it tries to apply the PoW to.

When using pool/farm mining as shown, I don't need a geth (or eth) background process that syncs the blockchain.

Correct. If you mine the block, the address of the miner becomes the coinbase address and the miner automatically assigns itself the reward for that block.

So geth is only needed for administration tasks (create/list accounts, show balance etc.) and I can add the --nodiscover and --maxpeers 0 arguments (or other flags?) to disable blockchain syncing.

geth is a full client meaning it can also mine. Setting those flags prevents geth from synchronizing with the block chain (it won't be downloaded).

Do I need to open the ethereum listen port 30303 for proper functioning (e.g. to get payouts)?

No, that port is only used for peer discovery. When you submit the block with the valid PoW and it is accepted by the network (remainder of peers) they will each synchronize their local copy of the block chain meaning that your client will synchronize as well.