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?


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.

  • 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. Nov 29 '15 at 15:41
  • 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 Dec 2 '15 at 3:01
  • 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. Jan 30 '16 at 23:39
  • is it possible to add multiple -bind directives (e.g. to bind to IPv4 and IPv6) ? Jun 18 '17 at 9:55
  • Yes, you can specify -bind multiple times. Jun 18 '17 at 16:44

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