Cisco - Set default route per interface

If you want to set a different default exit route for your clients and servers you can use route-maps to achieve this, using policy-based routing.
With the following configuration the servers from the 10.39.30.0/24 network will use the default gateway 10.39.30.254 but the clients will use 172.18.254.254 as default gateway:

interface GigabitEthernet0/1.1
description Servers Network
encapsulation dot1Q 1 native
ip address 10.39.30.253 255.255.254.0
!
interface GigabitEthernet0/1.2012
description Clients Network
encapsulation dot1Q 2012
ip address 172.18.254.253 255.255.0.0
ip policy route-map lanhop
!
!
ip route 0.0.0.0 0.0.0.0 10.39.30.254
!
! -- This sets the default GW
!
access-list 100 permit ip 172.18.0.0 0.0.255.255 any
!
! -- This matches the entire 172.18.0.0/16 network
!
route-map lanhop permit 10
match ip address 100
set ip default next-hop 172.18.254.254
!
! -- This sets the default GW for the IPs matched by the previous acl.

NOTE:
This is a sample configuration for policy-based routing using the set ip default next-hop and set ip next-hop commands:

• The set ip default next-hop command verifies the existence of the destination IP address in the routing table, and… if the destination IP address exists, the command does not policy route the packet, but forwards the packet based on the routing table. if the destination IP address does not exist, the command policy routes the packet by sending it to the specified next hop.
• The set ip next-hop command verifies the existence of the next hop specified, and… if the next hop exists in the routing table, then the command policy routes the packet to the next hop. if the next hop does not exist in the routing table, the command uses the normal routing table to forward the packet.