Dear Sir,
Please check the below configuration.
while configuring routes you can make one the routes with high AD so that it will the primary route
Dual-homed environments with different ISPs have usually meant that BGP must be used and that both ISPs must support BGP routing. Throughout this tutorial, I will show you how you can have mulitple ISPs without BGP or provider independant IP addresses. Tracking objects provide a means of removing static routes if the ISP cannot be contacted.
Here is a small drawing:
hostname Router
!
ip cef
!####Establish sla monitors for use in tracking objects####!
ip sla monitor 1
type echo protocol ipIcmpEcho 12.34.45.1
threshold 3
frequency 5
ip sla monitor schedule 1 life forever start-time now
ip sla monitor 2
type echo protocol ipIcmpEcho 23.34.56.1
threshold 3
frequency 5
ip sla monitor schedule 2 life forever start-time now
!
!####Configure Tracking objects (referencing IP SLA monitor’s above)####!
track 101 rtr 1 reachability
!
track 102 rtr 2 reachability
!
!
!
!
!####Configure Interfaces with NAT####!
interface FastEthernet0
ip address 192.168.1.254 255.255.255.0
ip nat inside
!
interface s0/0
ip address 12.34.45.2 255.255.255.0
ip nat outside
!
interface s0/1
ip address 23.45.67.2 255.255.255.0
ip nat outside
!
ip classless
!####Configure gateway of last resort with tracking objects####!
ip route 0.0.0.0 0.0.0.0 12.34.45.1 track 101
ip route 0.0.0.0 0.0.0.0 23.45.67.1 track 102
!####Configure NAT statements for most outbound traffic####!
ip nat inside source route-map ISP1 interface s0/0 overload
ip nat inside source route-map ISP2 interface s0/1 overload
!####Configure NAT statements for your mail server####!
!(remember to setup dns for mail on both public IP addresses)!
ip nat inside source static tcp 192.168.1.10 25 12.34.45.2 25 route-map ISP1 extendable
ip nat inside source static tcp 192.168.1.10 25 23.45.67.2 25 route-map ISP2 extendable
!
!
access-list 10 permit 192.168.1.0 0.0.0.255
!
!####Configure route maps for reference in NAT statements####!
route-map ISP2 permit 10
match ip address 10
match interface s0/1
!
route-map ISP1 permit 10
match ip address 10
match interface s0/0
!
Regards
Arulkumar
