Additional Second Factors

Starting with version 2.0.6, LemonLDAP::NG lets you configure multiple instances of second factor authentication modules, in a manner similar to the Combination module.

Only the following Second Factor modules are compatible with this feature:

Using this option, lets you give your users a wider range of possible second factors. They could decide between using their work email or home email. And as an administrator you may now plug in more than one Second Factor solution through REST or external commands.


You can find the configuration for this feature in General parameters » Second factors » Additional second factors

  • Name: the technical name of this second factor, it should be all lowercase, and it is used as a sort key when second factors are displayed to the user

  • Type: what type of second factor you want to use

  • Label: what title to display in the 2F choice screen

  • Logo : URL path of a logo to display in the 2F choice screen

  • Level: authentication level that will be set if this 2F is used

  • Activation rule: If you leave this field empty, this second factor will always be enabled. You may use a perl expression to decide when this second factor is available.

    • $homeMail : this second factor will only trigger if the $homeMail session key exists

    • defined $hGroups->{'admin'} : this second factor will only trigger if the user is in the admin group

  • Registrable: allow users to register their own contact information, see below

  • Registration rule: The rule that decides when users can register this second factor. Leave it empty to use the same rule as the activation rule above

After adding your second factors, don’t forget to add overload parameters to them. You usually should at least give them different logos so that the user can tell the difference between two second factors of the same type.

See the parameters list page for a full list of parameters you may overload. Here are the most useful ones:

  • E-Mail
    • mail2fLogo

    • mailSessionKey

    • mail2fCodeRegex

    • mail2fSubject

    • mail2fBody

  • External
    • ext2fLogo

    • ext2fCodeActivation

    • ext2FSendCommand

    • ext2FValidateCommand

  • REST
    • rest2fLogo

    • rest2fVerifyUrl

    • rest2fVerifyArgs (must be a JSON object)

    • rest2fInitUrl

    • rest2fInitArgs (must be a JSON object)


New in version 2.0.16.

Enabling registration for an additional second factor allows the user to register their own E-Mail address, SMS number, etc.

This is only compatible with the Mail, REST and External command modules. These modules will received the registered contact information through the destination variable, which you can use in ext2FSendCommand or rest2fInitArgs.

Template customization

When using the “registration” option for additional second factors, all second factor types will use generic2fregister.tpl for registration and ext2fcheck.tpl. If you want to display different things (messages, forms, etc.) to the user for different second factor types, you can use the PREFIX variable in your templates.

For example, if you defined a homePhone and homeMail extra second factor and want to overload the prompt message, replace

<label for="generic">&#x2460; <span trspan="genericRegisterPrompt">Enter your contact information</span></label>


<label for="generic">&#x2460; <span trspan="<TMPL_VAR NAME="PREFIX">Prompt">Enter your contact information</span></label>

And then set define homePhonePrompt and homeMailPrompt translation keys.

You can also test for a particular second factor type

Some info specific to the homePhone 2FA type

Regex validation

When using the “registration” option for additional second factors, you might want to specify a validation regexp for the registered value: check that the phone number is properly formatted, that the e-mail address does not use a forbidden domain, etc.

In order to do this, you can define additional overload parameters:

  • generic2fFormatRegex: the regexp you want to use

  • generic2fFormatErrorLabel: the message label you want to show the user when this regexp fails. By default, generic2fFormatError is used.

Don’t forget to define a human readable translation for this label