An IP Address
When creating a SNAT, you can specify a particular IP address that you want the SNAT to use as a translation address.
A SNAT pool
Specifying this value allows you to specify an existing SNAT pool to which you want to map your original IP address.
Similar to a SNAT pool, the SNAT automap feature allows you to map one or more original IP
addresses to a pool of translation addresses. With the SNAT automap feature, you do not need to
create the pool. Instead, Local Traffic Manager effectively creates a pool
for you, using self IP addresses as the translation addresses for the pool.