Step 1
SSH into the Fortinet FortiGate 60D
Step 2
Enter the following commands to configure WAN1 to 1500
FGT60D4613044111 # config system interface
FGT60D4613044111 (interface) # edit "wan1"
FGT60D4613044111 (wan1) # set vdom "root"
FGT60D4613044111 (wan1) # set mtu-override enable
FGT60D4613044111 (wan1) # set mtu 1500
FGT60D4613044111 (wan1) # next
FGT60D4613044111 (interface) # end
