I'm fighting NAT 1:1 rule failure on a an MX250 right now, and 18.210 didn't seem to help any over any older firmware.
Our problem:
public IPs (not actual, but close representation)
WAN1
10.0.0.1/28 gateway
10.0.0.2 main IP
10.0.0.3 secondary IP for certain traffic NATed to 192.168.0.11 (this works perfectly on legacy non Meraki router)
WAN2
11.0.0.2 main IP
- 1:1 NAT setup for LAN IP 192.168.0.11 to 10.0.0.3 port forwarding port 80 for non-secure informational data.
- of course normal port forward doesn't do anything since the traffic is not incoming on 10.0.0.2
- zero traffic allowed to or from 192.168.0.11 with 1:1 NAT turned on for 10.0.0.3
- outbound only traffic is good from 192.168.0.11 with no NAT or 1:MANY NAT (tried 1:MANY just for fun.) but still no incoming traffic allowed.
- Contacted ISP to clear ARP tables, still no traffic incoming.
With input from Meraki Support, we tried a number of scenarios, including messing with traffic shaping, and flow preferences. Very confusing as to why with NAT there is no incoming traffic allowed no matter what inbound ports are defined to allow traffic from a non-primary IP that still within the subnet. Seems like a serious Meraki bug that needs attention.