Chapter 19 Troubleshooting : Common questions : How to check the bridging information in Transparent mode : How to check the bridging information
  
How to check the bridging information
To list the existing bridge instances on the FortiGate unit, use the following command:
diagnose netlink brctl list
Sample output:
#diagnose netlink brctl list
list bridge information
1. root.b fdb: size=256 used=6 num=7 depth=2 simple=no
Total 1 bridges
DH - need more description of what this means.