<p>Normally it should autodetect. Check for lines like these in debug.log:
<code>
AddLocal([2a02:91a:f3:21aa::1]:8333,1)
</code></p>

<p>If that's the case, Bitcoin Core is listening to it, and if another service can't reach it, it may be a network configuration problem or a problem with that service.</p>

<p>If it isn't, you can manually bind to an IP address (IPv4 or IPv6) using the <code>-bind</code> option.</p>

CC BY-SA 3.0
2015-11-29T15:41:19.647Z
I checked debug.log and the lines are there. I copy-pasted the addresses into bitnodes.21.co and it still says unreachable. I've got Comodo firewall. I tried disabling it temporarily but still got nothing.
DoaJC_Blogger
CC BY-SA 3.0
2015-12-02T03:01:35.480Z
I think Bitcoin Core is hearing requests on my IPv6 address and not responding. Before it synced, it would intermittently respond on IPv4 to bitnodes.21.co, but most of the time the website waited a while and timed out. During this initial sync period IPv6 immediately failed, however. Now IPv4 succeeds quickly and IPv6 takes a while to time out. I know something must be different, since my node would rarely respond at all before the sync. The fact that IPv6 now takes a while to fail as opposed to immediately reporting "unreachable" makes me think the request is getting to me but being rejected
DoaJC_Blogger
CC BY-SA 3.0
2016-01-30T23:39:37.393Z
Could it have anything to do with my being on AT&T Uverse, which uses a 6rd tunnel? I have gone to websites that test IPv6 support and they all say I have a perfect IPv6 connection.
DoaJC_Blogger
CC BY-SA 3.0
2017-06-18T09:55:46.290Z
is it possible to add multiple `-bind` directives (e.g. to bind to IPv4 _and_ IPv6) ?
lifeofguenter
CC BY-SA 3.0
2017-06-18T16:44:04.090Z
Yes, you can specify -bind multiple times.
Pieter Wuille
CC BY-SA 3.0
2015-11-29T15:13:58.397Z
2015-11-29T15:13:58.397Z
Pieter Wuille
<p>I know my ISP provides IPV6. It was previously broken, but restarting my router fixed it. I confirmed my IPV6 connectivity on several websites. Then I restarted Bitcoin Core so it would see the new IPV6 address on startup, but bitnodes.21.co says my IPV6 address can't be reached. Any advice?</p>

<bitcoin-core><p2p>
How do I make Bitcoin Core listen on IPV6?
DoaJC_Blogger
# How do I make Bitcoin Core listen on IPV6?

(Asked by: username_0 on 2015-11-29)

I know my ISP provides IPV6. It was previously broken, but restarting my router fixed it. I confirmed my IPV6 connectivity on several websites. Then I restarted Bitcoin Core so it would see the new IPV6 address on startup, but bitnodes.21.co says my IPV6 address can't be reached. Any advice?

**Tags:** bitcoin-core, p2p


---

## 1 answers

### Answer by username_1 on 2015-11-29. Score: 2

Normally it should autodetect. Check for lines like these in debug.log:
`AddLocal([2a02:91a:f3:21aa::1]:8333,1)`

If that's the case, Bitcoin Core is listening to it, and if another service can't reach it, it may be a network configuration problem or a problem with that service.

If it isn't, you can manually bind to an IP address (IPv4 or IPv6) using the `-bind` option.

> **Comments:**
> **username_0**: I checked debug.log and the lines are there. I copy-pasted the addresses into bitnodes.21.co and it still says unreachable. I've got Comodo firewall. I tried disabling it temporarily but still got nothing.  
> **username_0**: I think Bitcoin Core is hearing requests on my IPv6 address and not responding. Before it synced, it would intermittently respond on IPv4 to bitnodes.21.co, but most of the time the website waited a while and timed out. During this initial sync period IPv6 immediately failed, however. Now IPv4 succeeds quickly and IPv6 takes a while to time out. I know something must be different, since my node would rarely respond at all before the sync. The fact that IPv6 now takes a while to fail as opposed to immediately reporting "unreachable" makes me think the request is getting to me but being rejected  
> **username_0**: Could it have anything to do with my being on AT&T Uverse, which uses a 6rd tunnel? I have gone to websites that test IPv6 support and they all say I have a perfect IPv6 connection.  
> **username_2**: is it possible to add multiple `-bind` directives (e.g. to bind to IPv4 _and_ IPv6) ?  
> **username_1**: Yes, you can specify -bind multiple times.  

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