What does --zmq-pub tcp://127.0.0.1:18083 do?

--zmq-pub tcp://127.0.0.1:18083 tells your Monero node to publish live event notifications on port 18083, with access limited to your own computer. P2Pool can listen there to learn quickly when your node sees a new block, so it can update the work your miner receives.

What each part means

You add this option when starting monerod, the program that runs a Monero node. A node checks Monero’s blocks and transactions and shares them with other nodes.

Here is how to read the option:

• --zmq-pub turns on a ZeroMQ publishing endpoint. ZeroMQ is a messaging system that lets programs exchange information. “Publishing” means your node sends notifications that another program can subscribe to.
• tcp:// tells it to use TCP, a standard way for programs to communicate over a network, including within one computer.
• 127.0.0.1 is the loopback address. It always means “this computer.”
• 18083 is the port number: the numbered connection point where the notifications are available.

This is an address for software to connect to, not a web page you open in your browser.

Why P2Pool uses it

P2Pool lets you mine with other people without putting a central pool operator in charge of your rewards. It needs information from a Monero node to keep its mining work current.

Your node’s ZeroMQ feed provides prompt notifications instead of making P2Pool repeatedly ask whether something has changed. When a new Monero block arrives, P2Pool can respond quickly and refresh the work it distributes.

That helps reduce time spent working on an outdated block. It does not make your processor calculate hashes faster, increase the block reward, or guarantee a payout.

This option also does not start P2Pool or start mining. It only enables the notification feed on your node. You still need to run P2Pool and connect your mining software to it.

How it fits into your setup

A basic node startup command containing the option looks like this:

monerod --zmq-pub tcp://127.0.0.1:18083

This shows the relevant option, not a complete configuration for every setup.

P2Pool also uses your node’s RPC interface, a separate connection for asking questions and requesting information, such as mining block templates. A block template is the starting information used to build a candidate block.

These connections have different jobs:

• RPC: P2Pool requests information from your node.
• ZeroMQ: Your node pushes event notifications to P2Pool.

On Monero’s main network, RPC commonly uses port 18081; the notification endpoint shown here uses 18083. They are not interchangeable.

What localhost means for access

With 127.0.0.1, programs on another computer cannot connect directly to this endpoint. That is a useful default when P2Pool and monerod run on the same machine.

If P2Pool runs elsewhere, its own 127.0.0.1 points to that other machine—not your node. Containers can create a similar separation.

You would need an appropriate private connection or carefully configured network access. Do not expose the endpoint publicly just to fix a connection error.

The bottom line

This option gives P2Pool a local, live notification feed from your Monero node. Keep the address and port matched to your P2Pool setup, and remember that it complements RPC rather than replacing it.