In Linux, if you use two network cards, you will encounter a situation that you can only use one of the network cards to access. This problem is caused by the routing table, so you need to use split-table routing to deal with it. Following bash scripts will help
##################################################
#for DMZ zone
if_wan=ens18
#for Local zone
if_lan=ens19
if_wan_ip1=`ip route|grep kernel|grep $if_wan|awk '{print $9}'`
if_lan_ip1=`ip route|grep kernel|grep $if_lan|awk '{print $9}'`
if_wan_ip2=`ip add list $if_wan|grep brd|grep $if_wan|awk -F '[ :/]+' '{print $3}'`
if_lan_ip2=`ip add list $if_lan|grep brd|grep $if_lan|awk -F '[ :/]+' '{print $3}'`
if [ "$if_wan_ip1" = "$if_wan_ip2" ];then if_wan_ip=$if