L2TP clients are dog slow when connected through UTM Firmware version:9.601-5

Question

I recently updated my UTM (running on a small form factor i7 based machine). 
 
 After updating, internal clients that use L2TP (Cisco Meraki) to connect to other sites are finding terribly slow performance. 
 
 Nothing in the logs to indicate an issue. Prior to this, the older UTM firmware worked beautifully. Any thoughts on how to fix this, aside from reverting to the older OS? 
 
 Thanks

BAlfson · Accepted Answer

Do you see anything in the Intrusion Prevention log? My guess would be that you need an Exception in Intrusion Prevention for anti-UDP flooding for IPsec traffic from your LAN(s). 
 Cheers - Bob