Janusseal for Outlook SafeDomain Extension

Security safety net when sending from Outlook

Janusseal SafeDomain ExtensionJanusseal for Outlook's SafeDomain Extension provides users with a security policy safety net when sending messages from Microsoft Outlook. This safety net:

  • can warn them when sending sensitive messages to a large number of recipients
  • can prevent them from sending sensitive messages to a large number of recipients
  • can remove recipients from sensitive messages if there is no secure network to send it safely to them
  • can correct (promote) email addresses when the sender accidently uses a recipient's public email address for a sensitive message when they should have used their private network address


Modify Recipients Dialog

Janusseal for Outlook's SafeDomain Extension -
modifying the recipients of a message based on its
security classification and SafeDomain's knowledge
of the security ratings of external domains.



  • Configurable list of SMTP safe domains, to which the organisation has secure delivery channels, such as a Virtual Private Network link.
  • Each safe domain may have a different security rating; security ratings correspond to the security classifications used by your organisation.
  • One button click for senders to promote email addresses of unsafe recipients to their equivalent addresses in the safe domains.
  • One button click for users to remove unsafe recipients, where no safe domain exists.
  • Warns senders and/or blocks transmission if there is a high number of recipients for the message. The thresholds can be set on a per message classification basis, so warning/blocking can be triggered on a lower number of recipients for more sensitive messages.
    Blocking message box
  • Can set an appropriate Reply-To address for sent messages based on the security classification to ensure return messages are delivered by a sufficiently secure channel.
  • Expands (mailing) groups to their member recipients to a configurable number of levels (local user's contact groups, Exchange mailing groups, Exchange dynamic groups).
  • Works with sender's local contacts, Active Directory users and contacts or explicit SMTP addresses.
  • Audit trail of user warning and acceptance to Event Log or file.
  • Enable/Disable the Extension depending on message type (message, meeting request, assigned task, post).


  • Reduced risk of embarrasing leaks when user accidently sends sensitive message to numerous recipients or a group with many members.
  • Reduced chance of accidentally sending to the wrong recipient which is often caused by Outlook's autocompletion of email addresses.
  • Senders do not have to remember multiple email addresses for the same recipient - SafeDomain corrects (promotes) recipient addresses to use the appropriate address for the sensitivity of the message.
  • Senders do not have to wait for a bounce back message from their email gateway when a message cannot be securely sent to a recipient - they get immediate feedback from SafeDomain.
  • Enhanced security as SafeDomain actively prevents sensitive messages being sent over insecure channels.


    Janusseal for Outlook's SafeDomain Extension is only supported in environments which meet the following minimum specifications:

    • Janusseal for Outlook 2.3,
    • Microsoft Outlook 2003 or 2007, and
    • Microsoft Windows Windows XP Professional SP3, Windows Vista SP2 or Windows 7


    Example Use

    Janusseal for Outlook's SafeDomain Extension is well suited for use by Local Authorities (councils) in the United Kingdom that are connected to the Government Connect Secure Extranet (GCSX) and which use its GC Mail solution.

    In this scenario, Alice at MyCouncil wants to exchange emails with Carol at OtherCouncil (who is also connected to the GCSX). Using the GC Mail system, Carol has two valid email addresses that Alice could use to send her information:

    1. carol@othercoucil.gov.uk is used to send emails of no sensitivity (Not Protectively Marked or UNCLASSIFIED) as this address is reached via the Internet.
    2. carol@othercoucil.gcsx.gov.uk is used to send emails of PROTECT or RESTRICTED sensitivity a they go via the GCSX network which is rated up to RESTRICTED.

    Without Janusseal SafeDomain Extension, Alice has to be very careful she does not use the incorrect email address for Carol, particularly when sending her sensitive information. The likelihood of this happening is increased by Outlook's 'feature' of autocompleting email addresses as the sender types in the address.

    With Janusseal SafeDomain Extension it doesn't matter if she gets it wrong as SafeDomain will fix it for her by 'promoting' the email address when sending sensitive information. It will also detect if she has included other recipients in the message for which the message cannot be safely sent to them. When Janusseal SafeDomain Extension detects either of these things happening it will show the sender an extra dialog telling them it is going to modify the recipients of the message. An example of this is shown below for Alice sending to Carol2 and Ed2 (where Ed2 is a user with an Internet based email address).

    Modify Recipients Dialog

    Once Alice clicks the Send button the recipient list is corrected to ensure the necessary security for the message over its journey. If Alice clicks the Cancel button she can go back to the message and edit it herself.