for example to bypass VPN for a single app:
https://serverfault.com/a/704253
ip rule add fwmark 2 table 3 ip route add default via 10.0.0.1 table 3 ip route flush cache iptables -t mangle -A OUTPUT -p tcp --dport 465 -j MARK --set-mark 2
Maybe relax source path validation? See Stackoverflow!