I am trying to configure WAN redundancy across a pair of links, using ip sla to monitor link state and switch routes if one fails.
The design uses Loopback0 as a NAT interface, with the two WAN interfaces as transit networks. The ISP routers will have dynamic routing such that the IP assigned to Loopback0 will be accessible over either link.
The config currently looks like so:
track 100 ip sla 1 reachability ! interface Loopback0 ip address 126.96.36.199 255.255.255.254 ip nat outside ip virtual-reassembly in ! interface GigabitEthernet0/0 description COLT WAN ip address 188.8.131.52 255.255.255.254 ip virtual-reassembly in duplex full speed 100 no cdp enable ! interface GigabitEthernet0/1 description INSIDE LAN ip address 184.108.40.206 255.255.0.0 ip nat inside ip virtual-reassembly in duplex full speed 100 ! interface GigabitEthernet0/1/0 description VODAFONE INTERCONNECT switchport access vlan 100 no ip address duplex full speed 100 no cdp enable ! interface Vlan100 description VODAFONE WAN ip address 220.127.116.11 255.255.255.254 ip virtual-reassembly in ! ip route 0.0.0.0 0.0.0.0 18.104.22.168 track 100 ip route 0.0.0.0 0.0.0.0 22.214.171.124 200 ! ip sla 1 icmp-echo 126.96.36.199 source-ip 188.8.131.52 frequency 5000 ip sla schedule 1 life forever start-time now
The router can ping
184.108.40.206, and both of these can ping
220.127.116.11. I have also verified that the redundant routing works if one of the links are down, although this doesn't appear to have any relation to this NAT issue.
18.104.22.168/24 I am able to ping
22.214.171.124 but not