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Adding IPv6 interface into ifconfig worked but host unreachable when use it

Muhammad Ikhwan Perwira

6/8/23, 6:53 PM

I have VPS run on Ubuntu 20.04, I was asking to Customer Service of my VPS Provider, she said their service (VPS) currently is not supporting IPv6. Since she is not technical support, I believe my VPS itself support IPv6.

I said so because my VPS is responding another IPv6 when I ping my VPS. Not only ping, But also HTTP request with using IPv6. When I open my website which hosted in that VPS. I enter the IPv6 of my VPS in url form of my browser [xx:xx...:xx]:80 then it redirect to my domain. Since I intended setup redirect it in my VPS. That's why I more believe that's IPv6 is mine.

At first when I check ifconfig, yeah there are no IPv6 word that mention it. I manually add IPv6 with ifconfig command flags itself.

But unfortunately, when my VPS ping another IPv6 server, it said Host unreachable

So I guess that customer service is not true. My VPS have IPv6 although only for incoming connection even though unable to perform outcoming connection.

So Is it possible I can do Outcoming connection in my VPS with IPv6?

When I realized that my VPS has IPv6? It was when I login SSH with my another VPS with IPv6 only into my IPv4 only VPS. That's make me wonder why my IPv4 VPS accept that connection?

Edit: Output of ip -6 addr show

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1000
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
    inet6 2001:xxx:xxx:xxx:x:x:xxx:xxx/112 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::5054:ff:fe19:dd6c/64 scope link
       valid_lft forever preferred_lft forever

Output of ip -6 route show

::1 dev lo proto kernel metric 256 pref medium
2001:xxx:xxx:xxx:xxx:xxx:1b70:0/112 dev ens3 proto kernel metric 256 pref medium
fe80::/64 dev ens3 proto kernel metric 256 pref medium

Edit: I turned off WARP Tunnel (3rd party) (there's no wgcf interface anymore)

This is when I run ping google DNS for example ping 2001:4860:4860::8888 Output: ping: connect: Network is unreachable

Ofcourse it will work if I use that 3rd party (warp tunnel or wgcf interface that actually using proxy)

0 + 0

ipv6

ifconfig

interface

Nikita Kipriyanov

6/8/23, 7:05 PM

First thing you should do is to remove `net-tools` with ifconfig and friends. It is simply unsuitable for configuring modern Linux, especially IPv6. It is even not installed by default in Debian, for around 5 years. Use `iproute2`. Ok, please show us `ip -6 addr show` and `ip -6 route show`. Don't mask private addresses (`fe80` etc.)

Muhammad Ikhwan Perwira

6/8/23, 7:13 PM

Output of ```ip -6 addr show```, there are three. ```1: lo```,```2:ens3```,```538:wgcf```. Ignore wgfc, because it's from warp tunnel or third party so that my VPS can access IPv6 resource.

Muhammad Ikhwan Perwira

6/8/23, 7:15 PM

Output of ```ip -6 route show``` is ```::1 dev lo proto kernel metric 256 pref medium 2001:67c:2b0:db32:0:1:1b70:0/112 dev ens3 proto kernel metric 256 pref medium fd01:5ca1:ab1e:896f:1ec3:382e:a7db:601f dev wgcf proto kernel metric 256 pref medium fe80::/64 dev ens3 proto kernel metric 256 pref medium```

Muhammad Ikhwan Perwira

6/8/23, 7:16 PM

iproute2 is not default installed

Nikita Kipriyanov

6/8/23, 7:31 PM

I just noticed you are new here. Sorry if that was not obvious, can you please [edit your question](https://serverfault.com/posts/1093083/edit) and add info there instead? Don't post in comments, it's hard to read since formatting breaks.

Muhammad Ikhwan Perwira

6/8/23, 7:34 PM

@NikitaKipriyanov okay done.

Nikita Kipriyanov

6/8/23, 7:40 PM

I masked your public IPs. Ok, and so, you believe these 2001:....:4f78 is yours? Yes. Is that IP you are talking about? What did you ping where the network was unreachable? Also, I don't see a default IPv6 route in your routing table. That's strange, it is probably the cause. Were you following your hoster's instructions for enabling IPv6 carefully?

Muhammad Ikhwan Perwira

6/8/23, 7:49 PM

Yes, I believe that's my IPv6 IP. You can see in my edited question, just an example I ping google. However it's work when I use 3rd party or wgcf interface. I'm no wonder about it because it's actually using proxy. There's no default IPv6 route, if you see IPv6 global, it's because i was adding it manually. About hoster's instruction, what you mean with it? I don't feel I got any instruction.

Nikita Kipriyanov

6/9/23, 9:05 AM

What are instructions of your hoster? Can you link to them please? I am sure the problem is because there is no defautlt route.

Muhammad Ikhwan Perwira

6/9/23, 10:15 AM

I don't feel get any instruction from them. All I receive is their service (VPS) currently is not supporting IPv6. What link?

Nikita Kipriyanov

6/9/23, 10:56 AM

And so, what's the problem then? You know there is *no* IPv6 service. Why are you concerned with it? (And whatever, I think everything will be off topic from on now.)

Muhammad Ikhwan Perwira

6/9/23, 11:50 AM

So basically I can't add IPv6 manually

Nikita Kipriyanov

6/9/23, 1:42 PM

You can do this via VPN where the other endpoint *has* an connectivity. But this is, again, completely different question.

Muhammad Ikhwan Perwira

6/9/23, 3:00 PM

Yeah thank you,, that was I said when I said ```wgcf interface```

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Adding IPv6 interface into ifconfig worked but host unreachable when use it

TH: การเพิ่มอินเทอร์เฟซ IPv6 ลงใน ifconfig ใช้งานได้ แต่ไม่สามารถเข้าถึงโฮสต์ได้เมื่อใช้งาน

RO: Adăugarea interfeței IPv6 în ifconfig a funcționat, dar gazda nu a fost accesibilă atunci când o utilizați

RU: Добавление интерфейса IPv6 в ifconfig работало, но хост был недоступен при его использовании.

VI: Thêm giao diện IPv6 vào ifconfig đã hoạt động nhưng máy chủ không thể truy cập được khi sử dụng nó

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