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ISP Redundancy with SLA

Customer Had one router with a T1 and a DSL for back up.

We ere able to use IP SLA on the router and SLA on the ASA.  This worked out excellent.

We added NAT for the 'outside' as well as the 'failover'

static (inside,outside) 12.1.1.3 10.1.1.3 netmask 255.255.255.255
static (inside,outside) 12.1.1.4 10.1.1.4 netmask 255.255.255.255
static (inside,failover) 74.1.1.4 10.1.1.3 netmask 255.255.255.255
static (inside,failover) 74.1.1.3 10.1.1.4 netmask 255.255.255.255

Although it is understood that the one router is the single point of failure as well as no HA ASA, it does give him SOME layer of redundancy.  MX records are added and are obviouly unreachable until such time as the link fails.

SLA and IP SLA will continue to ping the primary T1 track IP until it is available.

Note:  you must add the source interface, if not, you may have a flopping issue where your ISP A's IP is pingable from ISP B.  The devices will think that it IS reachable and fail back only to find that they cannot ping and have to failover again and again......

SEE ATTCAHED JPG for the Diagram and the config

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