Linux多可支持255个路由表，查看当前路由表：
#https://www.haiyun.me
ip rule ls
0: from all lookup local
32766: from all lookup main
32767: from all lookup default 根据源IP或目标IP选择路由表：
echo '252 onovps'>>/etc/iproute2/rt_tables
#新建路由表ID与名称映射
ip rule add from 192.168.1.5 table onovps pref 32764
#新建路由表onovps，优先级32764
ip route add default via 192.168.1.2 dev pppoe-wan2 table onovps
#新建路由表onovps默认路由项
ip route flush cache
#刷新路由缓存基于iptables标记选择路由表：
ip rule add fwmark 20 table onovps pref 32763
#新建路由表，防火墙标记20的数据
ip route add default via 192.168.1.2 dev pppoe-wan2 table onovps
#默认路由
iptables -t mangle -APREROUTING -p udp --dport 53 -j MARK --set-mark 20
#标记数据查看当前路由表：
ip rule ls
0: from all lookup local
32764: from 192.168.1.5 lookup onovps
32765: from all lookup main
32766: from all lookup main
32767: from all lookup default 查看路由表onovps下路由项：
ip route ls table onovps
default via 192.168.1.2 dev eth1 标签：iptables, openwrt, route, 策略路由, openwrt/linux策略路由设置