Whitelist Slack workspaces for your network

If you’re an IT admin, you can use this guide to whitelist Slack workspaces using an SSL proxy within your corporate network. By limiting connections to your entire Slack org and/or to a list of external workspaces, you can prevent anyone on your network from signing in to a non-whitelisted workspace.

What can you whitelist? 

  • Your Slack workspace
  • An entire Enterprise Grid org and all of its connected workspaces
  • External workspaces outside your Enterprise Grid org, such as those belonging to vendors, contractors, or external clients

How whitelisting works

IT admins can configure an on-premises or cloud-based proxy server to intercept traffic to slack.com. The proxy inserts new HTTP headers (X-Slack-Allowed-Workspaces-Requester and X-Slack-Allowed-Workspaces) that lists the workspaces your employees can access.


Once enabled, your team will be able to access the whitelisted org and/or external workspace(s) and continue using Slack normally. If anyone tries to sign in to a workspace that isn’t on the whitelist, they’ll see an error message.


Whitelist workspaces for your network

Here’s what you’ll need to get started:

  1. Check your proxy server: Make sure your proxy server supports SSL interception. We recommend referring to your product or service for details on how to configure the HTTP header.
  2. Identify org IDs or workspace IDs: Reach out to your Customer Success Manager or contact us to get a list of your org and workspace IDs.
  3. Configure the following 2 HTTP headers:

    Header 1: Add the header X-Slack-Allowed-Workspaces-Requester and set its value to the org or workspace ID representing your account. If this is not done first, the next header will not work.

    Header 2: Add the header X-Slack-Allowed-Workspaces and set its value to a comma-separated list of allowed org and/or workspace IDs. These represent the orgs and/or teams that need to be whitelisted. 


Who can use this feature?
  • Workspace Owners and Admins
  • Plus and Enterprise Grid plans