Settings sized to your hashrate, by the pool's own rule.

One share every 15 seconds, on each connection.

The pool retunes each connection toward one share every 15 seconds. A worker it has not seen before opens at difficulty 512. The pool retunes when a share arrives, once eight shares or 15 seconds have passed since the last change, and the rig takes the new difficulty with its next job.

Put d= and a number in the Stratum V1 password and the pool pins that difficulty, with the retuning off for that connection. It re-reads the pin at most every 30 seconds and keeps it between 1 and 1,000,000,000,000.

One port for both, told apart by the first byte.

Stratum V2 encrypts the connection and proves it reaches this pool, with a key your miner pins. It has no password, so the pool sizes the channel from the hashrate your rig reports and from its shares.

Stratum V1 carries the d= pin in the password, rolls version bits through mining.configure and gives each connection an 8-byte extranonce2. The stock firmware on the Bitmain, MicroBT and Canaan models in the list connects over V1.

Three marketplaces, three pool forms.

Mining Rig Rentals sizes difficulty per device and publishes a range for each rig. This page sizes the pin per device and warns you when it falls outside that range. The pool never sends client.reconnect, the message that makes Mining Rig Rentals mark a pool incompatible.

NiceHash fills an order from many rigs and wants a pool difficulty of at least 500,000 at start and 1,000,000 once hashrate flows, so the pin never goes under the live floor.

Braiins Hashpower takes a URL and an identity, with no password, so a new identity opens at 512 and takes its difficulty with the next job. Keep the same identity and the pool starts each later connection where the last one ended. The 8-byte extranonce2 clears the 7 Braiins Hashpower asks for and the 4 NiceHash asks for.