Insert Username in HTTP Headers

Configure the firewall to include the domain and username in the traffic headers to allow other appliances to receive user identification information.
When you configure a secondary enforcement appliance with your Palo Alto Networks firewall to enforce user-based policy, the secondary appliance may not have the IP address-to-username mapping from the firewall. Transmitting user information to downstream appliances may require deployment of additional appliances such as proxies or negatively impact the user’s experience (for example, users having to log in multiple times). By sharing the user's identity in the HTTP headers, you can enforce user-based policy without negatively impacting the user's experience or deploying additional infrastructure.
When you configure this feature, apply the URL profile to your Security policy, and commit your changes, the firewall:
  1. Populates the user and domain values with the format of the primary username in the group mapping for the source user.
  2. Encodes this information using Base64.
  3. Adds the Base64-encoded header to the payload.
  4. Routes the traffic to the downstream appliance.
If you want to include the username and domain only when the user accesses specific domains, configure a domain list and the firewall inserts the header only when a domain in the list matches the Host header of the HTTP request.
To share user information with downstream appliances, you must first enable User-ID and configure group mapping.
To include the username and domain in the header, the firewall requires the IP address-to-username mapping for the user. If the user is not mapped, the firewall inserts
unknown
in Base64 encoding for both the domain and username in the header.
To include the username and domain in headers for HTTPS traffic, you must first create a decryption profile to decrypt HTTPS traffic.
This feature supports forward-proxy decryption traffic.
  1. Create or edit a
    URL Filtering Profile
    .
    The firewall does not insert headers if the action for the URL filtering profile is
    block
    for the domain.
  2. Create or edit an HTTP header insertion entry using predefined types.
    You can define up to five headers for each profile.
  3. Select
    Dynamic Fields
    as the header
    Type
    .
  4. Add
    the
    Domains
    where you want insert headers. When the user accesses a domain in the list, the firewall inserts the specified header.
  5. Add
    a new
    Header
    or select
    X-Authenticated-User
    to edit it.
  6. Select a header
    Value
    format (either
    ($domain)\($user)
    or
    WinNT://($domain)/($user)
    ) or enter your own format using the
    ($domain)
    and
    ($user)
    dynamic tokens (for example,
    ($user)@($domain)
    for UserPrincipalName).
    Do not use the same dynamic token (either
    ($user)
    or
    ($domain)
    ) more than once per value.
    Each value can be up to 512 characters. The firewall populates the
    ($user)
    and
    ($domain)
    dynamic tokens using the primary username in the group mapping profile. For example:
    • If the primary username is the sAMAccountName, the value for
      ($user)
      is the sAMAccountName and the value for
      ($domain)
      is the NetBios domain name.
    • If the primary username is the UserPrincipalName, the
      ($user)
      the user account name (prefix) and the
      ($domain)
      is the Domain Name System (DNS) name.
  7. (Optional) Select
    Log
    to enable logging for the header insertion.
  8. Apply the URL filtering profile to the security policy rule for HTTP or HTTPS traffic.
  9. Select
    OK
    twice to confirm the HTTP header configuration.
  10. Commit
    your changes.
  11. Verify the firewall includes the username and domain in the HTTP headers.
    • Use the
      show user user-ids all
      command to verify the group mapping is correct.
    • Use the
      show counter global name ctd_header_insert
      command to view the number of HTTP headers inserted by the firewall.
    • If you configured logging in Step 7, check the logs for the inserted Base64 encoded payload (for example,
      corpexample\testuser
      would appear in the logs as
      Y29ycGV4YW1wbGVcdGVzdHVzZXI=
      ).

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