FortiGate
FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
ggiovanni
Staff
Staff
Article Id 279816
Description This article describes the behavior when the FGCP monitor interface is running together with fail-detect on the same interface.
Scope

FortiGate HA FGCP, fail-detect are running on the same interface (port1).

Solution
  1.  Fail-detect feature only works on Primary FortiGate.
  2. HA takes precedence over the fail-detect feature.

 

Additional reference:

Fortigate FGCP monitor interface can trigger failover when the monitored interface is down Introduction to the FGCP cluster

 

Using FortiOS v7.0.X, failover is triggered immediately (<1 second) once the monitored interface goes down:

 

FGCP-Failover-time.JPG

 

The fail-detect feature will detect if one interface goes down, then it will trigger corresponding fail-alert interface changes to down

Fail-detect reaction time takes around 2 seconds after interface goes down, and 1 second after interface goes up:
Technical Tip: What is the reaction time of fail-detect

 

Testing scenario:

  • HA monitor interface port1:

 

config system ha

    set override disable
    set group-name "FGCP"
    set mode a-p
    set hbdev "port2" 0

    set monitor "port1"

 

  • Fail-detect enable on port1, shutdown port3 if port1 goes down:

 

config system interface
    edit "port1"
        set vdom "root"
        set mode dhcp
        set allowaccess ping https ssh http fgfm
        set fail-detect enable
        set fail-alert-interfaces "port3"

 

Testing result:

The fail-detect feature only works on the Primary Firewall. On the secondary firewall, if port1 goes down, the corresponding fail-alert interface (port3) is still up:

 

Secondary-llcf.png

 

HA monitor interface will run the first failover triggered if the primary firewall interface port1 goes down.
The fail-detect will not run (FG1 port3 still up), since failover is triggered first in this case:

 

primary-monitor-interface.png

 

Status on FG2 (New Primary/Active) - port1 up, port3 up:

 

new-primary-fg2.png

 

When FG1 port1 still down, bring down FG2 port1:

 

FGCP-Failover-SN.JPG

 

FG1 becomes primary, and port3 becomes down because fail-detect is working on the primary unit:

 

FG1-Active-LLCF.JPG

 

 

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