Electing the active firewall

The process of electing the active member of the cluster takes place when HA starts up.

The following is a flowchart of the election process:

Do note that firewalls can be forced to be active (Configuration > High availability > Advanced properties > Quality index). In this case, the firewall will be active even if its quality factor is lower. You are advised against using this option on clusters in production, as it is used only to debug configurations.

This process relies on the comparison of each firewall’s quality factor, which will be explained further in this section.

Understanding how the quality factor is calculated

The quality factor is derived from a mathematical formula that takes into account various indicators:

  • Status and weight of the firewall's active interfaces (HA interfaces are excluded from this calculation), including aggregated interfaces (LACP),
  • Status(es) of the hard disk(s),
  • Status of the TPM on models equipped with one,
  • Status of additional modules (network, power supply, fans, etc.) on higher range models.

Example of how the quality index of interfaces is calculated

In this example, only interfaces 1 (out), 2 (in) and 4 (dmz2) are taken into account, since the dmz1 interface is dedicated to HA. Do note that interface 2 (in) has connectivity issues:

The weights assigned to the interfaces are as follows:

The quality index of the interfaces for this firewall is therefore: (1x100 + 0x100 + 1x75) / (100 + 100 + 75)=63%

The indicator calculated according to this method will be included in the overall calculation of the quality factor that takes into account other parameters.