Just wanted to throw this out there in case anyone else is having similar issues. We have 50+ branch offices all with different ISP combinations but the with Meraki Firewalls that are connecting to ATT Business Fiber Modems that s2s to Fortigates and various other devices, it is a reoccurring problem for tunnels to remain "up" but traffic is unable to pass from one LAN to another and this occurs at random times. Meraki to Meraki is fine but for whatever reason, I believe those ATT modems are conflicting with the handshake between Meraki and non Meraki devices. I solved the issue by forcing non Meraki traffic to use the non ATT WAN but have not been able to find out what is going on with the ARIS modem that is causing the problem and have verified the modems to not have any type of firewall or nat enabled. Just want to make it clear that the ATT is straight pass through. No Nat and no firewall. Public IP addresses are directly on the MX. ... View more