A short note about dealing with UDP issues on daisy-chained managed ProCurve switches.
I noticed a funny problem on a AWMN node that uses two daisy-chained managed HP ProCurve switches.
The routers on one of the switches were not able to get NTP updates from the time-servers connected to the other switch.
The routers having the issues were running RouterOS with their ntp clients set to unicast. The same RouterOS routers could get ntp updates just fine from interfaces not attached to the switch.
OpenWrt routers on the same switch did not have any problems talking-to and synchronizing-with time-servers attached to the other switch.
What Solved it?
On the switch
Security -> Advanced Security -> Disable Auto DoS & Disable Storm Control