Source Interface of OPNsense initiating traffic

[dennis_u]

We usually configure a loopback management interface with an management IP for remote sites. This IP is used for HTTPS, SSH and SNMP from the main site to the remote device. This works well through the VPN tunnel.

However, this does not work well for the reverse way. The use case is: the OPNsense initiates a connection to the syslog server. The expectation is: the OPNsense box takes the MGMT interface as source interface. The reality is, that the WAN IP is taken.

I attach an image to make that more clear. How can I achieve the goal ?

[dennis_u]

Additional question: may it be helpful in this case to change the tunnel into a route based tunnel instead of a policy based tunnel?