Check user plugin

This plugin allows us to check session attributes, access rights and transmitted headers for a specific user and URL. This can be useful for IT Ops, dev teams or administrators to debug or check rules. Plugin DISABLED by default.


Just enable it in the manager (section “plugins”).

  • Parameters:

    • Activation: Enable / Disable this plugin

    • Identities use rule: Rule to define which profiles can be displayed (by example: !$anonymous)

    • Unrestricted users rule: Rule to define which users can check ALL users and attributes.

    • Hidden attributes: Session attributes not displayed except for unrestricted users

    • Attributes used for searching sessions: User’s attributes used for searching sessions in backend if whatToTrace fails. Useful to look for sessions by mail or givenName. Let it blank to search by whatToTrace only

    • Hidden headers: Sent headers whose value is masked except for unrestricted users. Key is a VirtualHost name and value represents a space-separated headers list. A blank value obfuscates ALL relative VirtualHost sent headers. Note that just valued hearders are masked.

  • Display:

    • Computed sessions: Rule to define which users can display a computed session if no SSO session is found

    • Persistent session data: Rule to define which users can display persistent session data

    • Normalized headers: Rule to define which users can see headers name sent by the web server (see RFC3875)

    • Empty headers: Rule to define which users can display ALL headers sent by LemonLDAP::NG including empty ones

    • Empty values: Rule to define which users can display empty values

    • Hidden attributes: Rule to define which users can display hidden attributes

    • History: Rule to define which users can display logins history


By example:

* => Auth-User mail Just ‘Auth-User’ and ‘mail’ headers are masked if valued.

* => ‘’ ALL valued headers are masked.

Unrestricted users can see the masked headers.


By example:

* Search attributes => mail, uid, givenName

If whatToTrace fails, sessions are searched by mail, next uid if none session is found and so on…

* Display empty headers rule => $uid eq "dwho" -> Only ‘dwho’ will see empty headers


Keep in mind that Nginx HTTP proxy module gets rid of empty headers. If the value of a header field is an empty string then this field will not be passed to a proxied server. To avoid misunderstanding, it might be useful to not display empty headers.


Be careful to not display secret attributes.

checkUser plugin hidden attributes are concatenation of checkUserHiddenAttributes and hiddenAttributes. You just have to append checkUser specific attributes.


This plugin displays ALL user session attributes except the hidden ones.

You have to restrict access to specific users (administrators, DevOps, power users and so on…) by setting an access rule like other VirtualHosts.

By example: $groups =~ /\bsu\b/

To modify persistent sessions attributes (‘_loginHistory _2fDevices notification_’ by default), edit lemonldap-ng.ini in [portal] section:

persistentSessionAttributes = _loginHistory _2fDevices notification_


When enabled, /checkuser URL path is handled by this plugin.


With federated authentication, checkUser plugin works only if a session can be found in backend.