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EMS Server With Custom Domain

For this guide, I will be using the domain element.io. I will set up EMS so that the Matrix usernames becomes @someone:element.io, and the Element client will be at https://chat.element.io/

From the guide at Get Your Own EMS Server, I will be replacing the EMS hostname ems-demo-staging.ems.host with element.ems.host

Custom domains are only supported with Element Enterprise Cloud plans.

Prerequisites

  • You own and control the domain you want to use
  • If you do not have a website on the domain you want to use with your EMS server:
    • You can create a CNAME DNS record for the domain. Some providers call this ALIAS or CNAME Flattening when used on the root of the domain (domain root = yourdomain.com, not something.yourdomain.com)
  • If you have a website on the domain you want to use with your EMS server:
    • Your website has HTTPS enabled using a valid certificate issued by a commonly recognized provider. For example, Comodo or LetsEncrypt.
    • You can serve plain-text JSON files at these exact paths
      • https://yourdomain.com/.well-known/matrix/client
      • https://yourdomain.com/.well-known/matrix/server
      • Note that these files do not and cannot have a file extension
    • You can add the header Access-Control-Allow-Origin: * to the client file on the web server

See also

Setup

Some providers for DNS and website hosting providers need special configuration. See Provider specific instructions at the bottom for known solutions.

  1. Follow steps 1 - 10 from Get Your Own EMS Server

  2. On step 10 from Get Your Own EMS Server, turn ON Custom DNS
    temp

  3. In the Custom Homeserver domain field, enter element.io

  4. Create two files on your website according to the instructions given.
    The path cannot be changed, but up to 30 redirects are supported.
    While not required, you should add the header Content-Type application/json to both files.

    1. https://element.io/.well-known/matrix/server

      {
    "m.server": "element.ems.host:443"
}

    2. https://element.io/.well-known/matrix/client

      You need to enable the CORS header Access-Control-Allow-Origin: * on the web server for this file. See https://enable-cors.org/ for instructions on how to do this.

      {
    "m.homeserver": {
        "base_url": "https://element.ems.host"
    },
    "m.identity_server": {
        "base_url": "https://vector.im"
    },
    "org.matrix.msc3575.proxy": {
        "url": "https://element.ems.host"
    }
}
    Optional Nginx-specific configuration

    If your web server is running Nginx, you can set this in the Nginx config instead of creating actual files.

    server {
    server_name element.io

    ...

    # Matrix well-known files
    location /.well-known/matrix/client {
        return 200 '{"m.homeserver":{"base_url":"https://element.ems.host"},"m.identity_server":{"base_url":"https://vector.im"},"org.matrix.msc3575.proxy":{"url":"https://element.ems.host"}}';
        add_header Content-Type application/json;
        add_header 'Access-Control-Allow-Origin' '*';
    }
    location /.well-known/matrix/server {
        return 200 '{"m.server": "element.ems.host:443"}';
        add_header Content-Type application/json;
    }
}

  5. Click Check again to verify that your .well-known files are configured correctly

    You can also verify your `.well-known` files from the command line

    Note the lines access-control-allow-origin: * and content-type: application/json

    1. On Mac or Linux, using the terminal

      $ curl -i https://element.io/.well-known/matrix/client
HTTP/2 200 
date: Fri, 31 Jul 2020 09:11:21 GMT
content-type: application/json
content-length: 129
set-cookie: __cfduid=x...; expires=Sun, 30-Aug-20 09:11:21 GMT; path=/; domain=.element.io; HttpOnly; SameSite=Lax
access-control-allow-origin: *
cf-cache-status: DYNAMIC
cf-request-id: 0...
expect-ct: max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
server: cloudflare
cf-ray: 5...

{
    "m.homeserver": {
        "base_url": "https://element.ems.host"
    },
    "m.identity_server": {
        "base_url": "https://vector.im"
    },
    "org.matrix.msc3575.proxy": {
        "url": "https://element.ems.host"
    }
}

$ curl -i https://element.io/.well-known/matrix/server
HTTP/2 200 
date: Fri, 31 Jul 2020 09:11:25 GMT
content-type: application/json
content-length: 52
set-cookie: __cfduid=x...; expires=Sun, 30-Aug-20 09:11:25 GMT; path=/; domain=.element.io; HttpOnly; SameSite=Lax
access-control-allow-origin: *
cf-cache-status: DYNAMIC
cf-request-id: 0...
expect-ct: max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
server: cloudflare
cf-ray: 5...

{
    "m.server": "element.ems.host:443"
}

    2. On Windows, using PowerShell

      PS C:\Users\twilight> Invoke-WebRequest -Uri https://element.io/.well-known/matrix/client


StatusCode        : 200
StatusDescription : OK
Content           : {
                        "m.homeserver": {
                            "base_url": "https://element.ems.host"
                        },
                        "m.identity_server": {
                            "base_url": "https://vector.im"
                        },
                        "org.matrix.msc3575.proxy": {
                            "url": "https://element.ems.host"
                        }
                    }
RawContent        : HTTP/1.1 200 OK
                    Connection: keep-alive
                    Access-Control-Allow-Origin: *
                    CF-Cache-Status: DYNAMIC
                    cf-request-id: 0...
                    Expect-CT: max-age=604800, report-uri="https://repor...
Forms             : {}
Headers           : {[Connection, keep-alive], [Access-Control-Allow-Origin, *], [CF-Cache-Status, DYNAMIC], [cf-request-id, 0...]...}
Images            : {}
InputFields       : {}
Links             : {}
ParsedHtml        : System.__ComObject
RawContentLength  : 129


PS C:\Users\twilight> Invoke-WebRequest -Uri https://element.io/.well-known/matrix/server


StatusCode        : 200
StatusDescription : OK
Content           : {
                        "m.server": "element.ems.host:443"
                    }
RawContent        : HTTP/1.1 200 OK
                    Connection: keep-alive
                    Access-Control-Allow-Origin: *
                    CF-Cache-Status: DYNAMIC
                    cf-request-id: 0...
                    Expect-CT: max-age=604800, report-uri="https://repor...
Forms             : {}
Headers           : {[Connection, keep-alive], [Access-Control-Allow-Origin, *], [CF-Cache-Status, DYNAMIC], [cf-request-id, 0...]...}
Images            : {}
InputFields       : {}
Links             : {}
ParsedHtml        : System.__ComObject
RawContentLength  : 52

  6. You can continue without the .well-known files in place, but your server will have limited functionality until this is fixed

  7. In the Custom Client domain field, enter chat.element.io. This can be any domain, except the same as Custom Homeserver domain

  8. Create a CNAME DNS record with your DNS provider according to the instructions given
    chat.element.io. CNAME element.element.io.

  9. This shows how this is done with Cloudflare DNS. Depending on your DNS provider, this might be different. Consult the documentation for your provider. Note that Proxy must be turned off with Cloudflare.

  10. Back on EMS, click Check again. Note that sometimes it might take a while for your new DNS record to propagate. You can continue, but functionality will be limited. Check back with the Hosts tab on https://ems.element.io/user/hosting and click Rebuild Host once the DNS record is in place.
    temp

    You can also verify the CNAME DNS record using the command line

    1. On Mac or Linux, using the terminal

      $ dig chat.element.io CNAME

; <<>> DiG 9.10.6 <<>> chat.element.io CNAME
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57888
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;chat.element.io.   IN CNAME

;; ANSWER SECTION:
chat.element.io. 299 IN CNAME element.element.io.

;; Query time: 32 msec
;; SERVER: 1.1.1.1#53(1.1.1.1)
;; WHEN: Fri Jul 31 10:21:56 BST 2020
;; MSG SIZE  rcvd: 91

    2. On Windows, using PowerShell

      PS C:\Users\twilight> Resolve-DnsName -Name chat.element.io -Type CNAME

Name                           Type   TTL   Section    NameHost
----                           ----   ---   -------    --------
chat.element.io                 CNAME  299   Answer     element.element.io

  11. Continue from step 11 on Get Your Own EMS Server

Provider-specific instructions

GitHub Pages

If you are hosting your website with GitHub Pages, add this to the Jekyll config file _config.yml

include:
  - .well-known

Microsoft Azure

If you are using Microsoft 365 / Azure to manage your domain or the rest of your infrastructure, please use the following instructions to host the .well-known/matrix URI (RFC 8615).

In this section, we will configure Azure to serve https://yourdomain.com/.well-known/matrix/client and https://yourdomain.com/.well-known/matrix/client.

The summary of steps is as follows:

  • prepare json files
  • create a Storage account then enable a Static website
  • upload the json files to .well-known/matrix/ in the $web container
  • create a CDN and an endpoint for this container
  • create a CNAME DNS entry for your custom domain, pointing to your CDN endpoint
  • associate your custom domain to your CDN endpoint

Prepare client and server .well-known files locally

On your computer, prepare two plain text files called client and server (again, notice the lack of file extension such as ".txt") which contain the following:

client
{
    "m.homeserver": {
        "base_url": "https://your-tenant.ems.host"
    },
    "m.identity_server": {
        "base_url": "https://vector.im"
    },
    "org.matrix.msc3575.proxy": {
        "url": "https://your-tenant.ems.host"
    }
}

Remember to replace your-tenant by the name of your EMS tenant.

server
{
    "m.homeserver": {
        "base_url": "https://your-tenant.ems.host:443"
    }
}

Remember to replace your-tenant by the name of your EMS tenant.

You will be uploading these shortly.

Create a Storage account and Static website

Storage account

In the Azure Portal, create a Storage account.

Screenshot 2023-11-10 at 14-20-46 Microsoft Azure.png

The name needs to be unique to Azure. yourdomainwellknown is an option that should work well in most scenarios.

Performarce can be left to Standard.
Redundancy should be set to Geo-redundant storage (GRS) as the .well-known URI will be a core part of your EMS deployment.
You can leave all other options to their default or change them to fit your specific deployment scenario.

Finally, click create.

Static website

Once the Storage account is created, you will need to create a Static website in this Storage account.
In the Storage account overview, choose "Static website", in the Data management section.

Screenshot 2023-11-10 at 15-15-32 Microsoft Azure.png

You do not need to provide a specific Index document name or Error document path.

Enabling the Static website in your Storage account will automatically create a $web storage container to which you can upload the json text files which will be served at the .well-known URI.

Go to "Containers", in the "Data storage" section, to upload the client and server files you prepered earlier.

Click on the $web container, then chose "Upload", which will open a panel on the right.

When uploading the client and server files, make sure to open the "advanced" part of the upload panel and choose to upload to a specific folder: .well-known/matrix/

Azure: Storage account: upload .well-known/matrix/

Create a CDN, CNAME DNS entry for your custom domain and Custom domain name for the CDN endpoint

Creating a CDN is needed because Azure does not allow serving HTTPS over a custom domain using only a Storage account Static website. To do so, a CDN is necessary.

Create a CDN endpoint

Go back to your Storage account's main view and choose "Front Door and CDN" in the Security + Networking section, to create a CDN endpoint.

Azure: Storage account: CDN: endpoint

Service type: Azure CDN is sufficient, the more advanced features of Azure Front Door are not necessary here.

If you need to create a new profile, you may call the Profile name and Endpoint name as you wish.
For consistency, it is suggested to call them yourdomainwellknown as previously.

For Origin host name, pick your Static website.

For Query string caching behaviour, pick Ignore Query String, although this setting is not important in our context.

Once your endpoint is deployed, go to the resource, then go to your endpoint's further settings by clicking on it. Make note of its hostname (rfc8615demo.azureedge.net in our example) as you will need it shortly.

Azure: CDN: overview

Create CNAME DNS entry for your custom domain

You will now create a DNS entry for your custom domain, a CNAME pointing to your Azure CDN endpoint's hostname. How to do so exactly will depend on who hosts your DNS servers. The specifics of this are beyond this documentation, but the following general information should be sufficient.

In your DNS provider's admin panel, add a DNS entry with the following details:

  • Type: CNAME
  • Domain: your custom domain, such as yourdomain.com
  • Target: your Azure CDN Endpoint's hostname, such as rfc8615demo.azureedge.net in our example

Once created, this DNS entry may take some time to propagate, but in most cases will be picked up quickly by Azure, as needed in the next step.

Associate your custom domain with your CDN Endpoint

In the endpoint's settings, choose "+ custom domain" to start adding your custom domain. A panel will open on the right.

Enter your custom domain: yourdomain.com and finally, click add.

If the CNAME entry can be seen by Azure, after a few minutes your custom domain should be associated with your CDN Endpoint.

Final result

https://yourdomain.com/.well-known/matrix/client and https://yourdomain.com/.well-known/matrix/server are now served over HTTPS by Azure.

You should now have the following resources in your Azure account:

  • Storage account
  • Front Door and CDN Profile
  • Endpoint

Resources

  • https://learn.microsoft.com/en-us/azure/cdn/cdn-create-a-storage-account-with-cdn
  • https://learn.microsoft.com/en-us/azure/cdn/cdn-storage-custom-domain-https
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