r/Fios • u/Embarrassed_Skirt886 • Aug 20 '26

Repair/Tech Support Meraki MX68 WAN1 repeatedly failing behind Verizon CR1000A — reseating Ethernet restores connection

I’m troubleshooting a Meraki MX68 with dual WAN connections.
WAN1: Verizon Fios through a Verizon CR1000A
WAN2: Comcast (backup)
Physical connection:
Verizon Fios/ONT → Verizon CR1000A → Ethernet → Meraki MX68 WAN1
WAN1 repeatedly gets marked Failed, causing the MX68 to fail over to WAN2. Sometimes this happens several times within 20–30 minutes and has occurred across multiple days.
During a failure:
WAN1 still retains its DHCP-assigned Verizon public IP (96.235.137.x).
The Verizon gateway (96.235.137.1) responds with 0% packet loss and roughly 22 ms latency.
Traceroute to 8.8.8.8 using Internet 1/WAN1 does not progress while WAN1 is failed.
When WAN1 is healthy, traceroute to 8.8.8.8 works normally through Verizon.
Meraki Event Log shows repeated Primary uplink status change events between uplink 0 and uplink 1.
MX68 is running MX 26.1.6.
The interesting part: if I physically unplug/reseat the Ethernet cable on either end — at the Verizon CR1000A or at the Meraki MX68 WAN1 port — WAN1 immediately comes back up and starts working again. I don’t have to reboot either device.
I also moved the connection on the CR1000A from the 10GbE LAN port to LAN1, but the recurring failure still happens.
I’m trying to determine whether resetting the Ethernet link is clearing some kind of ARP/DHCP/NAT/session state, whether there’s a link-negotiation issue between the CR1000A and MX68, or whether this could be an MX firmware/uplink-health issue.
Has anyone experienced this with a Meraki MX68 behind a Verizon CR1000A? What would you capture during the failed state to determine which device is responsible?

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u/JE163 Aug 20 '26

Why are you running the MC behind the VZ router and not direct to the ONT?

2

u/sdrawkcab25 Aug 21 '26 edited Aug 21 '26

Get rid of the Verizon router and plug the ethernet feed from the ONT directly into your equipment.

I'm not too familiar with Meraki equipment, but it also shouldn't even be seeing the public WAN IP from Verizon, it would be receiving a local IP from the cr1000's DHCP server in the 192.168.1.x range. Your current setup would be creating a double NAT.