When using alternate public-ip resolution and ipv6 networking, node prefers ipv6 and is sidelined as being offline.

[haight6716]

Describe the bug
When:

• using an external IP resolution service via the public-ip-resolution-service option
• using a server with an ipv6 address
• calling getNodeIP
• only the ipv6 address is returned as "ip"
• only ipv6 clients can connect inbound
• stats.avax.network decides the node is offline

To Reproduce

• Configure a server on a network behind ipv4 NAT but with a public ipv6 address.
• Configure avalanchego to use opendns for self-address identification
• Start the node.

Expected behavior
Node should appear healthy on stats.avax.network. It does not.

Screenshots

    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"info.getNodeIP"
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/info
{"jsonrpc":"2.0","result":{"ip":"[2601:602:8e00:ce98:86c5:2292:57ec:656b]:9651"},"id":1}

Operating System
Ubuntu 12.04

Additional context
Discussed in node-support discord:
https://discord.com/channels/578992315641626624/620633143002660874/1246927981780271205

Possible enhancement would be to publish both ip and ipv6 keys, as appropriate, in the info.getNodeIP API result. Let clients decide which they prefer. Currently it seems a single node can serve only ipv4 or ipv6, never both. This might lead to a bifurcated network in the worst case.

This suggests that an ipv6 node will always be shown as "offline" by stats.avax.network. The stats-tracker should also be fixed to avoid this - ipv6 addresses should be acceptable public ips, but if the stats server has no ipv6 address, it cannot connect.

Workarounds

• Use UPnP to fetch your public IPs, by removing the public-ip-resolution-service config option.
• Set your public IP manually by using the public-ip config option.

[StephenButtolph]

When I attempt to connect to the IP linked above, it appears not to be dial-able:

dial tcp [IP]:port: connect: no route to host

I don't think this is an issue with anything not supporting IPv6... It seems like the service is reporting an IP that isn't dial-able. This isn't necessarily unexpected...

Possible enhancement would be to publish both ip and ipv6 keys, as appropriate, in the info.getNodeIP API result.

These IPs are gossiped throughout the p2p network. It is expected for a node to report what IP they are dial-able at. I don't think it's reasonable for nodes to report multiple IPs to connect to. (Similarly, DNS servers only report a single IP for each DNS request.)

This suggests that an ipv6 node will always be shown as "offline" by stats.avax.network.

stats.avax.network does support ipv6 addresses as far as I know.

[haight6716]

You are probably getting 'no route to host' due to your own lacking ipv6 infrastructure. I assure you it is routable from here. That said, I'm no longer listening on that IP because I used the workaround to bring my node back online. The same server is listening on port 80, so you can try that to see how it should work:

This should work:

ETA - IP changed: 2601:602:8e00:ce98:36fd:86c:8e35:9aa0

$ telnet 2601:602:8e00:ce98:86c5:2292:57ec:656b 9651
Trying 2601:602:8e00:ce98:86c5:2292:57ec:656b...
Connected to 2601:602:8e00:ce98:86c5:2292:57ec:656b.

Multiple IPs are completely reasonable. DNS allows the client to decide while making the query - either asking for A or AAAA records. With the default being both. Note also multiple IPs are returned, even for one protocol via DNS. See google's result:

$ dig any www.google.com

; <<>> DiG 9.18.18-0ubuntu0.22.04.2-Ubuntu <<>> any www.google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 65219
;; flags: qr rd ra; QUERY: 1, ANSWER: 11, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;www.google.com.			IN	ANY

;; ANSWER SECTION:
www.google.com.		110	IN	A	74.125.199.105
www.google.com.		110	IN	A	74.125.199.147
www.google.com.		110	IN	A	74.125.199.104
www.google.com.		110	IN	A	74.125.199.103
www.google.com.		110	IN	A	74.125.199.106
www.google.com.		110	IN	A	74.125.199.99
www.google.com.		110	IN	AAAA	2607:f8b0:400e:c02::6a
www.google.com.		110	IN	AAAA	2607:f8b0:400e:c02::93
www.google.com.		110	IN	AAAA	2607:f8b0:400e:c02::63
www.google.com.		110	IN	AAAA	2607:f8b0:400e:c02::67
www.google.com.		21410	IN	HTTPS	1 . alpn="h2,h3"

If stats.avax.network does support v6, can you show an example of a v6 node being reported as online?

I agree stats.avax.network does not support v6 IPs. And that's a problem if avalanchego does support ipv6. All v6 nodes will be reported incorrectly as "not online" even though they are participating in the network, accepting connections on 9651.

V6 gets no respect.

[haight6716]

To check your own v6 infrastructure, try connecting to google's v6 webserver:

$ telnet 2607:f8b0:400e:c02::6a 80
Trying 2607:f8b0:400e:c02::6a...
Connected to 2607:f8b0:400e:c02::6a.
Escape character is '^]'.

Proof the IP is listening publicly (dialable):

http://www.ipv6scanner.com/cgi-bin/main.py

No respect

Jk, thanks for all you do! Lemme know what I can do to help, I know a little go.

[StephenButtolph]

Looking into it - thanks for all the info

[haight6716]

I lost electrical power a few hours ago. I'll update with my new IP whenever I get back online.

New v6 IP on my node you can test against:
2601:602:8e00:ce98:e50b:f01e:251f:e293
2601:602:8e00:ce98:36fd:86c:8e35:9aa0 (I swear I don't typically reboot this often)

Running servers on a consumer internet connection, whee! But seriously, comcast is pretty rock solid and fast. kudos also for the proper /64 ipv6 delegation from them. Say what you want about the customer-facing stuff.

ETA:

I set up a test node, NodeID-KAAKyFf5rSAXCdEDyC8hWzJFkLJPBN4qX , that does not have the workaround applied. You can see it here:
2601:602:8e00:ce98:3252:fd81:354:a31e

I might shut it down in a few days, but ping me and I can fire it back up.

[StephenButtolph]

So, just to update here... As reported it seems like IPv6 isn't as well adopted as I thought 😓.

I suspect a large number of nodes are unable to make outbound IPv6 requests... Which means that nodes that choose to report IPv6 IPs will not be considered dial-able by these nodes.

Looking around there seem to be around 20 nodes on mainnet reporting IPv6 IPs.

This isn't necessarily the end of the world... But can impact network connectivity for those nodes.

[haight6716]

Thanks for the update. v6 is a hot mess in general, but bit by bit we move that way.

IMO we need a plan for getting to a future where most nodes are v6. Some thin clients are v6-only already. They will require a v6 server. Ideally we can mix-and-match, serving on 4/6, connecting to other clients on either, depending on our preference.

Some thoughts, if I were emperor:

• my initial suggestion, a new ipv6 key in the getNodeIP result.
• Only look for v4 addresses on IP discovery systems.
• V6 addresses don't need discovery - pick up any public v6 address your interface has assigned to it.
• Detect routeable v6 by connecting to a well-known v6 address (www.google.com).
• As a server, if v6 is routable, publish your v6 address.
• As a client, if v6 is routable, prefer connecting to other nodes' v6 address.

I don't see why nodes should even be required to have ipv4, but that's getting pretty far ahead of the ball.

ETA: I have no personal need for this to be fixed at this point - I'm using v4 ok now, but it seems in the best interest of the project long-term. Definitely does not need to be a priority for my sake.

I suspect v6 may be higher performance in some cases because it avoids layers of NAT, or allows jumbograms on LANs or .. ?.

Interesting: https://serverfault.com/questions/513942/convenient-public-ipv6-test-addresses

[haight6716]

I'm going to shut down the test node for now, but will record some evidence about it first.

From the ipv6 test node:

$ uptime
 10:27:22 up 1 day, 21:52,  1 user,  load average: 0.49, 0.41, 0.43

$ curl -sX POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"info.getNodeID"
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/info|json_pp 
{
   "id" : 1,
   "jsonrpc" : "2.0",
   "result" : {
      "nodeID" : "NodeID-KAAKyFf5rSAXCdEDyC8hWzJFkLJPBN4qX",
      "nodePOP" : {
         "proofOfPossession" : "0x91bacccddd77a95247bb909845f6ad20f6c47753380e5c17d360563b64c1ac7c465730bd3cbab8b0c47fbc51e4ecfe1a108c53224faa169cb67e453a23794c29d4820e69e4d08684b95e2433190267c253d1e95e9db63c0b7fcad0f6f2b2a158",
         "publicKey" : "0x8dc561321417fd71d407c125fe357fab799e3f16b4f4b7417feafdd43f56e4e42b56f4d9c156f0e258ebeaeae4b061ec"
      }
   }
}

$ curl -sX POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"info.getNodeIP"
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/info|json_pp 
{
   "id" : 1,
   "jsonrpc" : "2.0",
   "result" : {
      "ip" : "[2601:602:8e00:ce98:c86c:ebfe:8351:4cc8]:9651"
   }
}

From my production node - it can see the test node:

$ curl -sX POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"info.peers",
    "params": {
        "nodeIDs": ["NodeID-KAAKyFf5rSAXCdEDyC8hWzJFkLJPBN4qX"]
    }
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/info|json_pp 
{
   "id" : 1,
   "jsonrpc" : "2.0",
   "result" : {
      "numPeers" : "1",
      "peers" : [
         {
            "benched" : [],
            "ip" : "192.168.0.1:35726",
            "lastReceived" : "2024-06-06T10:35:24-07:00",
            "lastSent" : "2024-06-06T10:35:24-07:00",
            "nodeID" : "NodeID-KAAKyFf5rSAXCdEDyC8hWzJFkLJPBN4qX",
            "objectedACPs" : [],
            "observedSubnetUptimes" : {},
            "observedUptime" : "99",
            "publicIP" : "[2601:602:8e00:ce98:3252:fd81:354:a31e]:9651",
            "supportedACPs" : [],
            "trackedSubnets" : [],
            "version" : "avalanchego/1.11.4"
         }
      ]
   }
}

And finally stats.avax.network:

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