Pool Port
The pool port is the number at the end of the connection address, like :3333. One pool listens on several ports, and the choice between them sometimes decides whether your ASIC connects at all.
What a pool port is
The full address looks like stratum+tcp://pool:3333. First comes the protocol, then the host and the port. 3333 has historically been the main one for pools, with 443, 25, and other backups living nearby for the times when 3333 is closed.
It is not the pool that closes it, it is the network between you: an office firewall, a hotel router, a mobile carrier, a hosting facility with strict rules. Such networks only let familiar ports out, like 443, which is exactly why pools listen on it: miner traffic gets through where everything else is locked.
stratum+ssl is a separate story, an encrypted connection on its own port. It hides the contents of the exchange from middlemen. Your provider still sees where the traffic goes, so this is data protection, not anonymity.
Different ports of the same pool sometimes mean different modes: another region, another job difficulty, a solo branch. Reading the pool's connection page beats copying the first config you find on a forum.
The short version
| Where it sits | after the colon: stratum+tcp://pool:3333 |
| Main one for most pools | 3333 |
| Backup for strict networks | 443 |
| Encryption | stratum+ssl on a separate port |
| Who blocks it | firewall and provider, not the pool |
What to do when the miner won't connect
Switch the port to a backup from the pool's page, most often to 443. That fixes most 'pool unreachable' cases in strict networks.
Check the address letter by letter: a stray space or an old host from someone else's config gives the same symptom as a closed port.
Fill in backup pools with different ports: the main line on 3333, the backup on 443. The ASIC will cycle through them itself.
In someone else's network, at a facility or an office, ask about outgoing firewall rules before hauling your miners there.
Example from practice
An ASIC moved from home to a hosting facility and stopped seeing the pool, the config untouched. At home outgoing 3333 was open, at the facility the firewall only lets web ports out. Changing the port in the address to 443 brought the worker up within a minute, nothing else in the config was touched.
Related terms
Where to go next on the site
Software
- Software firmware
Numbers
Questions and answers
Which port to pick when all of them are open
The main one from the pool's page, usually 3333. Keep the backups in the config as a second line, so you never switch by hand.
Does the port change your income
No, a port is a door, not a rate plan. The fee and the payout scheme stay the same whichever pool port you use.
Why would a pool use port 443, that one is for websites
That is exactly why: 443 is open in almost any network, because ordinary web traffic goes through it. The pool listens there so miners can work even behind strict firewalls.
How the terms connect
Every link in the chain is clickable. Orange marks where you are now.
Looking for an ASIC miner
The catalog holds 212 models. You can compare them by hashrate and by joules per terahash, then plug your own rate into the calculator and see what stays in your pocket.
Page written and checked by Denys Klimchuk. Updated .