linux how to config route etc/network/interfaces?

Question

how to config route in etc/network/interfaces ? i want add 3 route in eth0 and eth1

i have try to configure like this:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
        address 192.168.82.168
        network 192.168.82.0
        netmask 255.255.255.0
        broadcast 192.168.82.255
        gateway 192.168.82.251
        mtu 1500

auto eth1
iface eth1 inet static
        address 192.168.32.164
        network 192.168.32.0
        netmask 255.255.255.0
        broadcast 192.168.32.255
        mtu 1500
post-up route add -net 192.168.32.0 netmask 255.255.255.0 gw 192.168.32.251 dev eth1
pre-down route add -net 192.168.32.0 netmask 255.255.255.0 gw 192.168.32.251 dev eth1
post-up route add -net 192.168.33.0 netmask 255.255.255.0 gw 192.168.33.251 dev eth1
pre-down route add -net 192.168.33.0 netmask 255.255.255.0 gw 192.168.33.251 dev eth1

but it doesn't work,i insert in command:

#route

the result print out:

 Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.82.251  0.0.0.0         UG    0      0        0 eth0
192.168.32.0    192.168.32.251  255.255.255.0   UG    0      0        0 eth1
192.168.32.0    *               255.255.255.0   U     0      0        0 eth1
192.168.82.0    *               255.255.255.0   U     0      0        0 eth0

Solution

Welcome to stackexchange. Please read this on cross-posting the same question on several stackexchange sites.

Now, to your question. The short answer: it does work. In details:

the route next after default in route printout:

192.168.32.0 192.168.32.251 255.255.255.0 UG 0 0 0 eth1

is the result of

post-up route add -net 192.168.32.0 netmask 255.255.255.0 gw 192.168.32.251 dev eth1

in your interfaces script. The second route to net 192.168.33.0/24 via gateway 192.168.33.251 is failed to add as there is no route to host 192.168.33.251 known on the eth1 interface. Either you meant to say that the route to net 192.168.33.0/24 is via gateway 192.168.32.251, or you need to add an explicit route to 192.168.33.251 according to your network configuration.