# Connection #0 to host icp0.io left intact

**URL:** <https://forum.dfinity.org/t/connection-0-to-host-icp0-io-left-intact/33885>\
**Category:** Rust\
**Created:** [August 5, 2024, 3:19pm UTC](https://forum.dfinity.org/t/connection-0-to-host-icp0-io-left-intact/33885 "2024-08-05T15:19:35Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![jeevan42](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/jeevan42/32/17493_2.png) [@jeevan42](https://forum.dfinity.org/u/jeevan42)\
**Post date:** [August 5, 2024, 3:19pm UTC](https://forum.dfinity.org/t/connection-0-to-host-icp0-io-left-intact/33885/1 "2024-08-05T15:19:35Z")

</div>

I am encountering an issue while attempting to register a custom domain. When I run the following command:

// curl -sLv -X POST   
// -H ‘Content-Type: application/json’   
// [https://icp0.io/registrations](https://icp0.io/registrations)   
// --data @- \<\<‘EOF’  
// {  
// “name”: “[jeevankumar.me](http://jeevankumar.me)”  
// }  
// EOF

I receive an error message indicating that the domain is missing from the canister’s list of known domains. The specific error is:

domain is missing from canister l6urk-aiaaa-aaaal-ajo6a-cai list of known domains

- Trying 147.28.156.118:443…
- Trying 2604:1380:40e1:4704:5000:48ff:fedf:c138:443…
- Immediate connect fail for 2604:1380:40e1:4704:5000:48ff:fedf:c138: Network is unreachable
- Trying 2604:1380:40e1:4701:5000:59ff:fe4d:3ea2:443…
- Immediate connect fail for 2604:1380:40e1:4701:5000:59ff:fe4d:3ea2: Network is unreachable
- Trying 2604:1380:40e1:4703:5000:48ff:fedf:c137:443…
- Immediate connect fail for 2604:1380:40e1:4703:5000:48ff:fedf:c137: Network is unreachable
- Trying 2604:1380:40e1:4702:5000:48ff:fedf:c136:443…
- Immediate connect fail for 2604:1380:40e1:4702:5000:48ff:fedf:c136: Network is unreachable
- Connected to [icp0.io](http://icp0.io) (147.28.156.118) port 443 (#0)
- ALPN, offering h2
- ALPN, offering http/1.1
- CAfile: /etc/ssl/certs/ca-certificates.crt
- CApath: /etc/ssl/certs
- TLSv1.0 (OUT), TLS header, Certificate Status (22):
- TLSv1.3 (OUT), TLS handshake, Client hello (1):
- TLSv1.2 (IN), TLS header, Certificate Status (22):
- TLSv1.3 (IN), TLS handshake, Server hello (2):
- TLSv1.2 (OUT), TLS header, Finished (20):
- TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
- TLSv1.2 (OUT), TLS header, Certificate Status (22):
- TLSv1.3 (OUT), TLS handshake, Client hello (1):
- TLSv1.2 (IN), TLS header, Finished (20):
- TLSv1.2 (IN), TLS header, Certificate Status (22):
- TLSv1.3 (IN), TLS handshake, Server hello (2):
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- TLSv1.3 (IN), TLS handshake, Encrypted Extensions (8):
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- TLSv1.3 (IN), TLS handshake, Certificate (11):
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- TLSv1.3 (IN), TLS handshake, CERT verify (15):
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- TLSv1.3 (IN), TLS handshake, Finished (20):
- TLSv1.2 (OUT), TLS header, Supplemental data (23):
- TLSv1.3 (OUT), TLS handshake, Finished (20):
- SSL connection using TLSv1.3 / TLS\_AES\_256\_GCM\_SHA384
- ALPN, server accepted to use h2
- Server certificate:
- subject: CN=boundary.dfinity.network
- start date: Jul 16 17:08:26 2024 GMT
- expire date: Oct 14 17:08:25 2024 GMT
- subjectAltName: host “[icp0.io](http://icp0.io)” matched cert’s “[icp0.io](http://icp0.io)”
- issuer: C=US; O=Let’s Encrypt; CN=R10
- SSL certificate verify ok.
- Using HTTP2, server supports multiplexing
- Connection state changed (HTTP/2 confirmed)
- Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
- TLSv1.2 (OUT), TLS header, Supplemental data (23):
- TLSv1.2 (OUT), TLS header, Supplemental data (23):
- TLSv1.2 (OUT), TLS header, Supplemental data (23):
- Using Stream ID: 1 (easy handle 0x5605771ceec0)
- TLSv1.2 (OUT), TLS header, Supplemental data (23):

> POST /registrations HTTP/2  
> Host: [icp0.io](http://icp0.io)  
> user-agent: curl/7.81.0  
> accept: _/_  
> content-type: application/json  
> content-length: 30

- TLSv1.2 (OUT), TLS header, Supplemental data (23):
- We are completely uploaded and fine
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
- old SSL session ID is stale, removing
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- TLSv1.2 (OUT), TLS header, Supplemental data (23):
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- TLSv1.2 (IN), TLS header, Supplemental data (23):  
\< HTTP/2 400  
\< server: nginx  
\< date: Sat, 03 Aug 2024 14:30:34 GMT  
\< content-length: 81  
\< x-request-id: ab0bf6b4-d100-7de7-1c51-046a3543642f  
\< access-control-allow-origin: \*  
\< access-control-allow-methods: HEAD, POST  
\< access-control-allow-headers: DNT,User-Agent,X-Requested-With,If-None-Match,If-Modified-Since,Cache-Control,Content-Type,Range,Cookie,X-Ic-Canister-Id  
\< access-control-expose-headers: Accept-Ranges,Content-Length,Content-Range,X-Request-Id,X-Ic-Canister-Id  
\< access-control-max-age: 600  
\<
- TLSv1.2 (IN), TLS header, Supplemental data (23):
- Connection #0 to host [icp0.io](http://icp0.io) left intact  
domain is missing from canister l6urk-aiaaa-aaaal-ajo6a-cai list of known domains

folder structure:

> Public  
> .well-known  
> ic-domains  
> .ic-assets.json

ic-assets.json:

[  
{  
“match”: “.well-known”,  
“ignore”: false  
}  
]

ic-domains:  
[jeevankumar.me](http://jeevankumar.me)  
www.jeevankumar .me

---

<div class="post-metadata">

**Author:** ![rbirkner](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbirkner](https://forum.dfinity.org/u/rbirkner)\
**Post date:** [August 5, 2024, 4:19pm UTC](https://forum.dfinity.org/t/connection-0-to-host-icp0-io-left-intact/33885/2 "2024-08-05T16:19:56Z")

</div>

Hello @jeevan42

The error you are receiving means that your canister is missing the file/the domain is not listed. You can check whether the file is there by issuing a simple curl command:

```auto
$ curl -s https://l6urk-aiaaa-aaaal-ajo6a-cai.icp0.io/.well-known/ic-domains

```

When I do it for your canister, I get the index.html back:

```auto
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width" />
  <title>Jeevan Kumar Portfolio</title>
  <base href="/" />
  <link rel="icon" href="/favicon.ico" />
  <script type="module" crossorigin src="/assets/index-7b17def4.js"></script>
</head>

<body>
  <div id="root"></div>

</body>

</html>%

```

This means the file doesn’t actually exist and it just falls back to that. Make sure you follow the structure outlined in [the docs here](https://internetcomputer.org/docs/current/developer-docs/web-apps/custom-domains/using-custom-domains#step-2-create-a-file-named-ic-domains-in-your-canister-under-the-well-known-directory-containing-the-custom-domain).

---

<div class="post-metadata">

**Author:** ![jeevan42](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/jeevan42/32/17493_2.png) [@jeevan42](https://forum.dfinity.org/u/jeevan42)\
**Post date:** [August 7, 2024, 7:28pm UTC](https://forum.dfinity.org/t/connection-0-to-host-icp0-io-left-intact/33885/3 "2024-08-07T19:28:42Z")

</div>

Thanks for the reply, i deployed it first on main net then requested for registration. and it works now. [https://jeevankumar.me](https://jeevankumar.me) working now.