GRE Traffic not handled but blocked by OPNSense except promiscous mode is enabled

[elschman]

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Describe the bug

We do have two vlan interfaces vI1 and vI2 with 10.160.5.0/24 and 10.160.6.0/24 and on the same physical IF. GW is the firewall. A host A in vl1 (10.160.5.3) has an GRE tunnel configured to host B (10.160.6.3) in vl2

firewall rules allowing all IP traffic between these networks. PING,SSH and HTTPS working fine. But GRE traffic is not forwarded between both interfaces except tcpdump is started on firewall shell or the interfaces configured for in promiscuous mode

Expected behavior

Traffic flowing as long ip rules allowing traffic

Environment

OPNsense 23.7.12-amd64 FreeBSD 13.2-RELEASE-p7 OpenSSL 1.1.1w

NET HW <Broadcom BCM57412 NetXtreme-E 10Gb Ethernet>