<p>Port 8333 is only relevant for inbound connections. Opening it allows other nodes to start talking with your node.</p>
<p>That said, a Bitcoin node can fully participate in the network even if you don't allow inbound connections (to port 8333). It'll use outgoing connections, which start from random higher unprivileged ports and connect to port 8333 of another node. If you can allow incoming connections that's good for the health of the Bitcoin network, otherwise outbound connections are <a href="https://bitcoin.stackexchange.com/a/88147/117651">functionally equivalent</a>.</p>
<p>Bitcoin Core can also offer a <a href="https://en.bitcoin.it/wiki/API_reference_(JSON-RPC)#JSON-RPC" rel="nofollow noreferrer">JSON-RPC</a> interface on port 8332, so if you need that, act accordingly.</p>

CC BY-SA 4.0
2021-04-09T16:14:18.360Z
2021-04-11T14:31:53.237Z
2021-04-11T14:31:53.237Z
leevancleef
<p>Does port 8333 need to be listed in <code>TCP_OUT</code> in a firewall or in <code>TCP_IN</code> as well?</p>

<port><firewall>
Does port 8333 need to be opened as TCP_OUT or TCP_IN?
Ben Muircroft
# Does port 8333 need to be opened as TCP_OUT or TCP_IN?

(Asked by: username_0 on 2021-04-09)

Does port 8333 need to be listed in `TCP_OUT` in a firewall or in `TCP_IN` as well?

**Tags:** port, firewall


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## 1 answers

### Answer by username_1 on 2021-04-09. Score: 2 | Accepted answer

Port 8333 is only relevant for inbound connections. Opening it allows other nodes to start talking with your node.

That said, a Bitcoin node can fully participate in the network even if you don't allow inbound connections (to port 8333). It'll use outgoing connections, which start from random higher unprivileged ports and connect to port 8333 of another node. If you can allow incoming connections that's good for the health of the Bitcoin network, otherwise outbound connections are [functionally equivalent](https://bitcoin.stackexchange.com/a/88147/117651).

Bitcoin Core can also offer a [JSON-RPC](https://en.bitcoin.it/wiki/API_reference_(JSON-RPC)#JSON-RPC) interface on port 8332, so if you need that, act accordingly.


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