Thank you for the question about the multi-wan. That, along with other posts, finally got my attention to what appears to be the detail I needed to update.
The rule for the WAN interface where the external connection was allowed in had to have "Reply-To" set to the WAN interface. Once I made that change, the issue appears to be fixed (needs more testing, but it appears to work at the moment).
NOTE: I have my Destination NAT set to where I need to manually make the rules ("Manual"). HOWEVER, in the attempting to fix this issue, I did also try "PASS" and "Register rule", both of which should have theoretically fixed this problem if opnsense was setting its own rules appropriately -- but it did not. It did not work until I manually changed the rule and set the Reply-to option.
The rule for the WAN interface where the external connection was allowed in had to have "Reply-To" set to the WAN interface. Once I made that change, the issue appears to be fixed (needs more testing, but it appears to work at the moment).
NOTE: I have my Destination NAT set to where I need to manually make the rules ("Manual"). HOWEVER, in the attempting to fix this issue, I did also try "PASS" and "Register rule", both of which should have theoretically fixed this problem if opnsense was setting its own rules appropriately -- but it did not. It did not work until I manually changed the rule and set the Reply-to option.
"