Hi,
I'm currently testing failover between 2 ISP using the one Cisco 3800.
The problem is once the primary link goes down, the backup is active using floating static but Internet.
Looking at the NAT trans and there is no trans on the backup link IP Address pool.
The challengin part of this project is that we only have 2 Ethernet Interface on the 3800 and both are already in use for WAN and LAN.
Below is my config:
interface GigabitEthernet0/0
description LINK TO PRIMARY LINK
ip policy route-map NAT-to-ISP1
ip address x.x.x.x 255.255.255.252
!
interface GigabitEthernet0/1
description LINK TO SWITCH STACK - 3560
no ip address
!
interface GigabitEthernet0/1.500
description LINK TO BACKUP LINK
ip policy route-map NAT-to-ISP2
ip address y.y.y.y 255.255.255.252
!
ip route 0.0.0.0 0.0.0.0 x.x.x.x name PRIMARY
ip route 0.0.0.0 0.0.0.0 y.y.y.y 50 name BACKUP
!
ip nat inside source route-map NAT-to-ISP1 interface GigabitEthernet0/0 overload
ip nat inside source route-map NAT-to-ISP2 interface GigabitEthernet0/1.500 overload
!
route-map NAT-to-ISP1 permit 10
match ip address NAT_ACL
match interface GigabitEthernet0/0
!
route-map NAT-to-ISP2 permit 10
match ip address NAT_ACL
match interface GigabitEthernet0/1.500
As you can see, the backup link is connected to our internal switch stack on gig0/1 and I have created a sub-interface assign access VLAN 500 on the switch port. We are not using dynamic routing on both WANS.
Once the primary link goes down, I can see the floating static adding the backup as the default gateway using AD.
Have I miss anything? I know the problem is NATing.
Thanks
