Bitcoin Forum

Hello,

I just setup a bitcoin node and I see some incoming connection with connection type "npr" and address like "127.0.0.1:33686".

What means "npr" and why the address looks like a local one?

Thanks and sorry for the naive question.

Just in case, do you know of any software that may try connect to local Bitcoin full node automatically? Some wallet (such as Ginger and Wasabi wallet) may do that automatically.


1. In this case, "npr" stands for "not publicly routable"
2. 127.0.0.1 is local address, where it's also called localhost or loopback address. It's used to perform communication between software on your device.

Thanks for your answer.

-> Just in case, do you know of any software that may try connect to local Bitcoin full node automatically? Some wallet (such as Ginger and Wasabi wallet) may do that automatically.

Actually I don't. I haven't connected a wallet yet. One of the incoming connection shows up as "70016/dsn.kastel.kit.edu/bitcoin:28.0.0/" which seems to be some school...

-> 1. In this case, "npr" stands for "not publicly routable"

Could that be a connection under i2p network by any chance?

-> 2. 127.0.0.1 is local address, where it's also called localhost or loopback address. It's used to perform communication between software on your device.

Ok got it!

Is that something I should worry about? As anyone I guess, I am concerned with privacy and security (not maniac but not laxist either).

Thanks a lot!

By default, Bitcoin Core accept incoming connection. I remember that website/university do some research and share data about Bitcoin, so i doubt it's malicious node. Although i believe that kind of connection should be categorized as either "ipv4" or "ipv6".


Most likely no.
1. AFAIK all I2P connection would show address with ".i2p" at the end.
2. I2P should be showed under "i2p" rather than "npr".


IMO, no.

Thanks again for giving your view on this.

Would you know where I could start to dig into this deeper?

Much appreciated

If you want to dig into Bitcoin Core details, you may want to visit https://bitcoin.stackexchange.com (https://bitcoin.stackexchange.com). But if you mean dig into Bitcoin technical detail, i would recommend  https://learnmeabitcoin.com/ (https://learnmeabitcoin.com/) and https://github.com/bitcoinbook/bitcoinbook/ (https://github.com/bitcoinbook/bitcoinbook/).

Non peer relay, meaning the connection isn't a standard p2p.Because connection is local and you connecting with yourself.

Then it has to be a Bitcoin related app you installed maybe a monitoring tool or self hosted block Explorer. But the summary is there's something else the node is communicating locally with.

if you mean to check the connection issue more then you can try https://bitcoincore.org/en/doc/ after selecting core version you can click on network and access getpeerinfo. This could give more info about connections.

No, I don't think this is what "npr" means.

I run my node solely over Tor. Onion is the only allowed connection type. My node has currently 10 outgoing connections to onion peers and 32 incoming connections from other nodes which are labeled npr "non publicly routable". Those incoming peer connections happily talk to my node, relay transactions and blocks and receive stuff from my node.


See excerpt from documentation by bitcoin-cli -netinfo help: