Technical Tip: FortiAuthenticator HA cluster overview
Description
This article describes the scope of a FortiAuthenticator HA cluster.
Scope
FortiAuthenticator.
Solution
FortiAuthenticator can work as a cluster offering redundancy and, in some configurations, balancing charges.
The configuration can be made on an L2 (Active/Passive) layer or an L3 (Active/Active) layer.
The following prerequisites must be achieved:
- Two FortiAuthenticator devices of the same model and platform.
- Both devices must run the same firmware version.
- All HA participants must have a valid license.
Active/Passive:
- One device operates in the primary role while the other operates as a backup in standby mode.
- The backup device monitors the primary through an HA interface.
- L2 communication is required between HA links. IPsec AES encrypts the connection. Heartbeat traffic is over port 720 UDP. The configuration is replicated every 2 seconds.
- Failover takes 30 seconds. Authentications required during the failover are lost.
- Administrative access to the secondary device is achieved with a unique IP address. This access is required to change HA settings, perform a firmware upgrade, or perform troubleshooting.
- To access the HA management GUI IP of the HA interface of both units, it is necessary to have a Workstation in the same subnet as the HA interface configured on the FortiAuthenticators.
Note: Backup units cannot allow configuration changes.
Active/Active (GEO HA):
- An L3 connection is required.
- A primary cluster can back up to another cluster.
- Only the following features are synchronized in this mode: Tokens and seeds, Local and remote users, group mappings, and token and user mappings.
Starting in firmware version 6.6, more configurations can be synchronized. This is optional; the settings are available under System -> Administration -> High Availability on the primary node. By default, the synchronization behavior is the same as in v6.5 and earlier.
- General troubleshooting methods:
execute tcpdump -i <HA-heartbeat-port> port 720 on CLI with tcpdump, filtering port 720 UDP (heartbeat traffic).
Running the capture generates output similar to the following:
execute tcpdump -i port3 port 720
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on port3, link-type EN10MB (Ethernet), snapshot length 262144 bytes
14:20:29.130045 IP 169.254.0.1.720 > helium-san.fortilab.net.720: UDP, length 200
14:20:29.455460 IP 169.254.0.2.720 > helium-san.fortilab.net.720: UDP, length 200
14:20:30.137985 IP 169.254.0.1.720 > helium-san.fortilab.net.720: UDP, length 200
14:20:30.452354 IP 169.254.0.2.720 > helium-san.fortilab.net.720: UDP, length 200
- Refer to this document on FortiAuthenticator tcpdump packet capture for more information: Technical Tip: How to run a Packet Capture with FortiAuthenticator.
- Look into detailed logs in FortiAuthenticator’s GUI: https://<fac_ip>/debug/slony.
- Collect report.dbg and send logs to TAC support for further analysis.
Related articles:
Technical Tip: How to configure FortiAuthenticator HA A-P cluster
Technical Tip: How to configure FortiAuthenticator load-balancing cluster
