How can one merge mine Townforge with Monero?

Question

Townforge, a fork of Monero, can be merge mined with Monero (https://townforge.net/faq/#faq-13).

How can one merge mine both blockchains ?

Answer 1

Merge mining can only be done if two chains use the same PoW algorithm. In this case, both Townforge and Monero use RandomX, and merge mining can be done using a standard pool miner such as xmrig, which can either be used with a pool or with the monero daemon.

Townforge includes a merge mining proxy which will sit between the miner and the monerod daemon, and will transparently alter the RPC communications between monerod and xmrig to allow merge mining Townforge too.

Note that for the following to work, monerod must first be patched with https://github.com/monero-project/monero/pull/6810 (once this PR is merged, this will not be needed anymore).

Consider a straightforward setup where a user is mining with xmrig to the monerod daemon:

monerod --rpc-bind-port 18081
xmrig --coin monero --url 127.0.0.1:18081 --daemon --user 4....

We will need to run the townforged daemon and the merge mining proxy, such that the proxy stands between monerod and xmrig:

monerod --rpc-bind-port 18083
townforged --rpc-bind-port 18881
townforge-merge-mining-proxy --rpc-bind-port 18081 --monero-daemon-address 127.0.0.1:18083 --aux-daemon-address 127.0.0.1:18881 --aux-wallet-address TF1....
xmrig --coin monero --url 127.0.0.1:18081 --daemon --user 4....

The proxy will connect to townforged too, and is set up with the Townforge address any block coinbase should be sent to. The xmrig command line does not change: while it was previously talking to monerod, it is now talking with the merge mining proxy, and does not see the difference.