Ethical Wall Operation Modes

Owned by Agat Support
Last updated: Apr 13, 2022 by Avi J. Levin (Unlicensed)
2 min read

Live mode

This is the regular operation mode of the Ethical Wall and it works as follows:

  1. SIP traffic from Skype for Business Front-End and\or Edge servers is being inspected if a cached policy is applied to it.

  2. Check if there is a pre-existing calculation in the database cache.

    1. If not, the SIP Filter will calculate the policy and store it in the database cache.

    2. If the calculation requires access to internal resources (UCMA or LDAP) and the SIP Filter is running on the Edge, the SIP Filter will query the Admin Portal API to get the policies.

  3. SIP filter caches the policy locally and enforces the calculated policy.

  4. The maintenance service keeps refreshing the database cache to verify validity.

Examples:

  1. In case the communication is allowed and pre-calculated:

    1. Alice@external.com sends a message "Hello!" to bob@internal.com

    2. This reaches the Edge/Front End, Edge/Front End forwards this to the SIP Filter

    3. SIP Filter checks in the Policy Cache and sees this already has been calculated.

    4. SIP Filter returns the found policy cache, which allows the traffic to bob.

  2. In case the communication is blocked and not pre-calculated:

    1. Eve@external.com sends a message "Hey!" to Bob@internal.com

    2. This reaches the Edge/Front End, Edge/Front End forwards this to the SIP Filter

    3. SIP Filter checks in the policy cache and doesn't find an entry, thus calculates and adds the calculation result as a record in the policy cache

    4. SIP Filter returns the calculated policy, which blocks the traffic to bob.

Learning Mode

This mode is designed to build a large cache in the database. While in learning more, only default policies are enforced by the SIP filter.

It is recommended to maintain this mode during a fresh deployment in order to establish a comprehensive enough cache.

This is due to the introduced load of calculating policies without a pre-existing cache that can hinder the normal Skype for Business operation and generate instabilities.

Example of the operation during Learning Mode:

  1.  Alice@external.com sends a message "Hello!" to Bob@internal.com

  2. This reached the Edge/Front End, Edge/Front End forwards this to the SIP Filter

  3. SIP Filter checks & returns the corresponding Default policy for this Traffic (Default external).

  4. SIP Filter inputs a new record to the Ethical Wall Policy Cache.

  5. The maintenance service finds the corresponding policy for this record.

  6. The maintenance service updates this cache in the database.