Header authentication

Overview

Header Authentication is an additional mechanism to prevent unauthorised parties from using the Cryptshare Mail Gateway as a relay to send emails to any domain (open relay). With enabled Header Authentication, all messages coming from trusted hosts will need to have a certain header value, otherwise they are discarded. Header Authentication can be enabled during the initial setup. This page describes how to configure it at a later time.

Configuration Steps

  1. Open /opt/cryptshare-mail-gateway/smtp-filter/config.properties in an editor.

  2. To specify the name of the required header, change the value of app.smtp.auth.header.name. Otherwise, the default value X-CS-AuthenticationKey is used.

app.smtp.auth.header.name = X-MyAuthenticationHeader

  1. To enable Header Authentication and specify the expected value of the header, change the value of app.smtp.auth.header.value. If you leave it empty or the line is commented out, Header Authentication will be disabled.

app.smtp.auth.header.value = my-expected-header-value

  1. Save the file.

  2. Restart the cmg-filter service:

systemctl restart cmg.filter
This header is removed by the Cryptshare Mail Gateway so that its confidential value is not made public. Do not specify any header that is required to remain in the message as the authentication header.