Symptoms Cisco RV34s comes with pre-defined Microsoft Azure IPSec profile, but seems it's impossible to set up a tunnel with Azure just using default settings. Diagnosis First, you can find messages in RV34x logs like follow:   charon: 11[NET] received unsupported IKE version 2.0 from (peer_IP), sending INVALID_MAJOR_VERSION info vpn charon: 11[NET] sending packet: from (site_IP)[500] to (peer_IP)[500] (40 bytes) info vpn charon: 11[ENC] generating INFORMATIONAL_V1 request 0 [ N(INVAL_MAJOR) ]   The issue is happening due to RV34x seems does not understand IKEv2. Currently Azure supports both modes of VPN gateways: route-based VPN (default) and policy-based. Here is a difference between (taken from https://docs.microsoft.com/en-us/azure/vpn-gateway/vpn-gateway-connect-multiple-policybased-rm-ps https://docs.microsoft.com/sv-se/azure/vpn-gateway/vpn-gateway-about-vpn-gateway-settings#gwsku ):    Azure PolicyBased VPN Gateway RouteBased VPN Gateway Azure Gateway SKU Basic Basic, Standard, HighPerformance, VpnGw1, VpnGw2, VpnGw3 IKE version IKEv1 IKEv2 Max. S2S connections 1 Basic/Standard: 10 HighPerformance: 30   So, it seems that a workaround could be to change the VPN mode on Azure side to the policy-based one, which could supply IPSec profile with IKEv1. Solution 1. On RV34x set up IPSec Profilre for Azure as follow: Phase 1: DH = group 2 Encryption = AES-256 Intergrity = SHA1 PFS = no Lifetime = 28800 Phase 2: Encryption = AES-256 Integrity = SHA-256 LIfetime = 3600   2. On RV34x set up IPSec Advanced Settings for profile: Keep-alive = Enabled Aggressive Mode = Disabled   3. On Azure site: Set up Virtual Connection to "policy-based VPN gateway" instead of "route-based" one.   Enjoy, but remember about Azure's restriction to allow 1 S2S connection only for policy-based VPN gateway IPSec.         ... View more