Important note about SSL VPN compatibility for 20.0 MR1 with EoL SFOS versions and UTM9 OS. Learn more in the release notes.

Sophos Firewall: Make your HTTPs CA available for download in the Captive Portal (and elsewhere)

Disclaimer: This information is provided as-is for the benefit of the Community. Please contact Sophos Professional Services if you require assistance with your specific environment.


    Table of Contents

    Overview

    This recommended read describes how to make HTTPS Scanning CA (certificate) available via the Captive Portal via base64 encoding and 'data' URI.

    Configuration Steps

    Step1. Download a copy of your SSL CA file from the Sophos Firewall ( Note: If you're using the built-in CA, it’ll save as file 'SecurityAppliance_SSL_CA.pem')

    Step2. Encode the whole file using base64 and output it as a single line.

    On Windows, you can use this powershell command:

    [System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes( (Get-Content -Raw SecurityAppliance_SSL_CA.pem) ))

    On a Mac or a Linux system, you can do this by running:

    base64 SecurityAppliance_SSL_CA.pem | tr -d '\n'

    In both examples, replace 'SecurityAppliance_SSL_CA.pem' with the path and filename of the your certificate as necessary.

    Step3.  Go to Authentication > web authentication > Captive portal appearance. In the Login Page Footer HTML text box, paste the following:

    <a href='data:application/x-x509-ca-cert;base64,

    Next, copy and paste the base64 block - output of the command in step 2.

    Finally, append the following text at the end of the base64 block:

    '>Download HTTPS certificate authority</a><p>By doing this, you consent to allow your HTTPS web traffic to be decrypted and scanned for security purposes</p>

    You should end up with something that looks like this:

     Step4. Click 'Preview' to see what it looks like, and check that the file downloads correctly when you click the link.

    Step5. Click Apply to save




    Corrected spacing for code
    [edited by: Erick Jan at 11:52 PM (GMT -7) on 30 Oct 2024]
    Parents
    • Just wanted to let you know that it appears on Step 3 your code has an unintentional space in it.

      It shows as this:

      < a href='data:application/x-x509-ca-cert;base64,

      When it should be this:

      <a href='data:application/x-x509-ca-cert;base64,

      Looks like the space after the '<' and before the 'a' shouldn't be there. My captive portal on SFOS v21 was not showing it as a link but rather just displaying the entire string on the captive portal until I removed the space then it worked correctly.

      Jack Bevington

    Reply
    • Just wanted to let you know that it appears on Step 3 your code has an unintentional space in it.

      It shows as this:

      < a href='data:application/x-x509-ca-cert;base64,

      When it should be this:

      <a href='data:application/x-x509-ca-cert;base64,

      Looks like the space after the '<' and before the 'a' shouldn't be there. My captive portal on SFOS v21 was not showing it as a link but rather just displaying the entire string on the captive portal until I removed the space then it worked correctly.

      Jack Bevington

    Children