<p>Bitcoin nodes do not have a unique identifier, and this is by design.</p>

<p>In fact, any property that allows someone on the network to verify whether two connections (even separated in time) are to the same node, is something we'd call a fingerprinting attack.</p>

<p>As such identification could be used to link transactions coming from the same node together, they are a potential privacy leak.</p>

CC BY-SA 3.0
2017-03-18T03:18:06.563Z
2017-03-18T03:18:06.563Z
Pieter Wuille
<p>I have a bunch of Bitcoin nodes supporting the Bitcoin network. Is there a way to tell if one of my servers is in fact running without installing a 3rd party software. Say I wanted to pay one of my users that hosts a Bitcoin server, but I don't want to pay him unless I can detect his Bitcoin server is indeed running. Is there some type of unique identifier to tell if one of my nodes is running?</p>

CC BY-SA 3.0
2017-03-17T21:00:34.877Z
If by unique identifier you mean IP address, sure. What else do you need?
Pieter Wuille
CC BY-SA 3.0
2017-03-17T21:58:45.360Z
what if my ip changes everytime my node reboots? i dont think detecting an ip would work.
Patoshi パトシ
CC BY-SA 3.0
2017-03-18T03:08:39.407Z
Well then you try connecting to the new IP, you know your own IP right?
Pieter Wuille
<bitcoind><server>
Is there a way to tell if a specific Bitcoin node is on the network?
Patoshi パトシ
# Is there a way to tell if a specific Bitcoin node is on the network?

(Asked by: username_0 on 2017-03-16)

I have a bunch of Bitcoin nodes supporting the Bitcoin network. Is there a way to tell if one of my servers is in fact running without installing a 3rd party software. Say I wanted to pay one of my users that hosts a Bitcoin server, but I don't want to pay him unless I can detect his Bitcoin server is indeed running. Is there some type of unique identifier to tell if one of my nodes is running?

**Tags:** bitcoind, server

> **Comments:**
> **username_1**: If by unique identifier you mean IP address, sure. What else do you need?  
> **username_0**: what if my ip changes everytime my node reboots? i dont think detecting an ip would work.  
> **username_1**: Well then you try connecting to the new IP, you know your own IP right?  

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## 1 answers

### Answer by username_1 on 2017-03-18. Score: 2

Bitcoin nodes do not have a unique identifier, and this is by design.

In fact, any property that allows someone on the network to verify whether two connections (even separated in time) are to the same node, is something we'd call a fingerprinting attack.

As such identification could be used to link transactions coming from the same node together, they are a potential privacy leak.


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