/etc/i2pd/i2pd.conf contains number of listening ports configuration (actually 10 or more when you look for “port”). Which ones should I open in firewall so other people can connect my node? Excluding ones that are meant for management of my node. I manage the node only locally.
So far I have only open/forwarded one port, one that is set a few lines below the line “## Port to listen for connections” that certainly allows relaying traffic for other I2P peers per the http://127.0.0.1:7070/ traffic stats.
Services HTTP Proxy Enabled
SOCKS Proxy Enabled
BOB Disabled
SAM Enabled
I2CP Enabled
I2PControl Disabled


i2p selects a random UDP+TCP port on first start that you have to open, the rest are usually only for internal use.
I have never used i2pd, but I think
i2pd portshould print which port it expects to be open. Alternatively you can set it yourself withi2pd port (your port)