Session Casting

Session Casting allows administrators to expose external facing URLs that will automatically launch a Kasm session. These Casting URLs can optionally be unauthenticated and protected by ReCAPTCHA, Referrer, and IP rate limits.

Administrators may find this feature useful for offering no-auth access to the Kasm environments.


Casting Workflow


  • Log into the Kasm Web UI as an administrator.

  • Click Casting.

  • Click Create New Config.


Casting Config




The unique identifier for a Casting URL. If 123abc is the key, users will launch sessions via the following URL https://my.kasm.server/#/cast/123abc


The Kasm Image to use for the created sessions.

Allow Anonymous

If checked, requests to the Casting URL will not require authentication. Instead the system will create an anonymous users account for each new request.

Require reCAPTCHA

When Allow Anonymous is enabled, administrators can choose to have requests validated by Google reCAPTCHA . To use this feature, the Google reCAPTCHA Private Key and Google reCAPTCHA Site Key properties must be set in the Server Settings.

Anonymous User Group

When Allow Anonymous is checked, the system will create new user accounts for each new request. These anonymous users accounts will automatically be added to the All Users Group and an additional Group defined here. Administrators can configure the appropriate Group Settings to configure permissions such as allow_kasm_downloads etc on this Group.

Limit Total Session

When enabled, the administrator can configure a maximum number of sessions that will be served via this Casting URL.

Sessions Remaining

Sets the total number of sessions that can be requested. This value will automatically decrement as new sessions are served. When the value reaches zero, users will receive an error when attempting to request subsequent sessions.

Limit Requests Per IP

When enabled, the system will limit the number of requests that will employ rate-limiting based on the source IP of the request. (e.g limiting requests to 1 sessions per 60 seconds)

Sessions Allowed

When Limit Requests Per IP is enabled, this value is used as the total number of sessions that are allowed for the given time period as defined in Within Seconds.

Within Seconds

When Limit Requests Per IP is enabled, this value sets the timeframe (in seconds) that is used for the source IP.

Kasm URL

If defined, this value will populate as the KASM_URL environment variable for created or assigned Staged Sessions. These values are often used in the Docker Exec Configs of the browser Images.

Allow Dynamic Kasm URL Parameter

When checked, the user is allowed to append a kasm_url query argument to the cast url. e.g https://kasm.server/#/cast/123? If present the system will use this value as the KASM_URL

Allow Dynamic Docker Network URL Parameter

When checked, the user is allowed to append a docker_network query argument to the cast url. e.g https://kasm.server/#/cast/123?docker_network=example_network The Image used must have Allow Network Selection enabled.

Error URL

If defined, the user will be pushed to this URL when an error (such as IP rate limit violation) occurs. If left blank, an internal error page is shown.

Disable Control Panel

When checked, the Control Panel widget is not shown for the sessions.

Disable Tips

When checked, the Tips dialogue is not shown when a user enters a session.

Enable Sharing

When checked, this session will automatically have sharing activated.

Disable Shared Fixed Resolution

When checked and the session is in sharing mode, the resolution will be dynamic. The resolution is typically fixed when a session enters sharing mode.

Restrict to Referrers

Administrators may chose to restrict where the Casting URLs can be accessed from. If a user were to click a Casting URL link that was embedded on a 3rd party website, the system can detect the website domain. It the address is not in the list defined in this setting, the request will be denied. Enter one domain (e.g per line. If the option is left blank, requests from all domains are accepted.

  • Fill out the form then click Submit.

  • A list of all Casting Configs is shown.


Casting Config List


Casting reCAPTCHA Check

Error Page

When an error occurs that prevents the user from loading a session via a Casting URL, the system will send the user to an internal error page with an appropriate error message. If desired, the administrator can chose to redirect the user to a page of their choosing by configuring the Error URL setting in the Casting Config.


Error Message