Hi @fcbob, It should have to work behind NAT. Try define the remote ID on Meraki side with the Sonicwall IP: The Remote ID of the remote peer. This is an optional configuration and can be configured to the remote peer’s UserFQDN (e.g. user@domain.com), FQDN (e.g. www.example.com) or IPv4 address as needed. Which of these values you use is dependent upon your remote device. Please consult its documentation to learn what values it is capable of specifying as its remote ID, and how to configure them (e.g. crypto isakmp identity for ASA firewalls https://documentation.meraki.com/MX/Site-to-site_VPN/MX_to_Sonicwall_Site-to-Site_VPN_Setup
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