pfSense

`/etc/rc.filter_synchronize` uses `guess_interface_from_ip()` which returns only first (top-down) interface from the `route_get($ipaddress)` output (which is slow, see #11475)

how to reproduce:
1) LAN (vtnet0) - 192.168.88.41/24, used for DHCP (failover IP on secondary - 192.168.88.42);
2) Create OpenVPN p2p instance with remote network 192.168.0.0/16;

now `guess_interface_from_ip("192.168.88.42")` returns 'ovpns1', cause it first in the `netstat -rn` output:

netstat -rn | grep 192.168.
192.168.0.0/16     10.78.78.2         UGS      ovpns2
192.168.88.0/24    link#1             U        vtnet0
192.168.88.41      link#1             UHS         lo0

see https://forum.netgate.com/topic/161152/strange-problem-dhcp-failover-after-upgrade-to-2-5-0-xmlrpc-bug