Troubleshooting Tip: HA Synchronization failure due to priority value in 'modem' interface

[jjdope]

Description	This article describes how to diagnose and work around the HA out-of-sync problem caused by the priority value in the 'modem' interface.
Scope	FortiGate.
Solution	The HA is out of sync due to configuration differences on the system.interface of the modem. Below is an example output from both the primary and secondary FortiGates. The current primary is JJ-01 and the secondary is JJ-02 JJ-01 (global) # diagnose sys ha checksum show global system.interface modem [name]='modem': 11325d912af10e25f6bcb92630b3f9ad [vdom]='root': af813d778dc917407271953725916b8d [mode]='pppoe': 632411fff2fc45f885c30ff48328f46d [distance]='1': 2776ea2c12bd88353378e4f38ad7dbda [priority]='0': 422564ccdae72258a309ba4b9381abaf [status]='down': 05dacc64cf3afdf7b1749ebc31aa9d82 [type]='physical': 39d37257932bbbeb5593b348f9a9ce57 [snmp-index]='11': 5f3edb8c0ea96286b8b35c11770c8fd9 JJ-02 (global) # diagnose sys ha checksum show global system.interface modem [name]='modem': 11325d912af10e25f6bcb92630b3f9ad [vdom]='root': af813d778dc917407271953725916b8d [mode]='pppoe': 632411fff2fc45f885c30ff48328f46d [distance]='1': 2776ea2c12bd88353378e4f38ad7dbda [status]='down': 05dacc64cf3afdf7b1749ebc31aa9d82 [type]='physical': 39d37257932bbbeb5593b348f9a9ce57 [snmp-index]='11': 5f3edb8c0ea96286b8b35c11770c8fd9 The difference is that in JJ-FW-01, the priority value is set to 0. The configuration is as given below: JJ-01 (global) # show system interface modem config system interface     edit "modem"         set vdom "root"         set mode pppoe         set distance 1         set priority 0         set status down         set type physical         set snmp-index 11     next end JJ-02 (global) # show system interface modem config system interface     edit "modem"         set vdom "root"         set mode pppoe         set distance 1         set status down         set type physical         set snmp-index 11     next end The integer value range for the priority value is 1 to 64435. JJ-01 (modem) # set priority priority Enter an integer value from <1> to <65535> (default = <1>). This configuration is a read-only setting, which means that even an admin with super_admin privileges is not allowed to configure this value. The following message will be displayed when the configuration to change the priority value is attempted. JJ-01 (modem) # set priority 1 cannot change read-only setting. Workaround: Perform a failover to make JJ-02 the primary. Reboot JJ-01 which was previously the primary, and allow it to reconnect to HA. This will restore the priority settings on the system interface modem to the default value of 1. The HA will remain in sync if JJ-01 is set to be the primary again.