Really Poor SMB performance
Fortinet to Fortinet, 100E to 60E, IPSec Tunnel, gigabit connection on the 100E and 400mbit on the 60E.
SMB transfers are slow, about 2 or 3mbps.
Have adjusted tcp-mss in the IPV4 policy for the indicated branch and on the IPSEC interface itself to 1306 (which is low but higher doesn't matter, when left at default it was fragmenting so I lowered it)
config sys interface
set tcp-mss 1306
config firewall policy
edit <policy number>
set tcp-mss-sender 1306
set tcp-mss-receiver 1306
(configured both legs of the firewall policy, inbound and outbound, on both firewalls)
Perhaps of note, IPSEC tunnels to Juniper firewalls perform normally (also have tcp-mss set to 1306) . . .
What setting am I missing?