I'm drawing a blank on a simple thing. I remember that I need to have 30303 open on tcp and udp for the listening and discovery. And I seem to remember that you need 30304/udp open.

But I'm not finding anythink that confirms this.

Maybe it's 30301, and not 30304 that I have to open for udp?

Can someone remind me?

1 Answer 1


These ports need to be opened on your firewall:

-- Port 30303 (TCP and UDP)

-- Port 30304 (UDP)

"Peer discovery is UDP only. This means that on 30303 you are using both TCP (ETH and LES protocols) and UDP (old peer discovery for finding ETH peers), on 30304 only UDP is used." (source)

This page mentions 30301 as an example: "In the following example, the node URL describes a node with IP address, TCP listening port 30303 and UDP discovery port 30301."

30301 is used by the bootnode util as default UDP discovery port.

  • That is what I remember. Okay thank you. Can you please explain in this answer what 30303 and 30304 do. Also, can you explain the relevance of 30301. Your quote doesn't make clear why this comes up. And that page is not where I read about 30301 so it might be floating around that 30301 is needed.
    – stone.212
    Commented Sep 24, 2017 at 22:38
  • 30301 is used by the bootnode util as default UDP discovery port. The page linked uses it as an example for a non default config.
    – Gaia
    Commented Sep 25, 2017 at 3:53
  • Ethereum clients use a listener (TCP) port and a discovery (UDP) port, both on 30303 by default. 30304/udp is the old peer discovery method. keep it open for backwards compatibility.
    – Gaia
    Commented Sep 25, 2017 at 3:55
  • And what does it mean "30301 is used by the bootnode util as default UDP discovery port?"
    – stone.212
    Commented Sep 25, 2017 at 4:52
  • see these answers for an explanation of the bootnode utility ethereum.stackexchange.com/questions/12503/…
    – Gaia
    Commented Sep 25, 2017 at 17:00

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