Because who needs split horizon dns anyway? When you’re using an ASA as your internet gateway, that is.

object network PrimaryServer

host 192.168.1.2

nat (inside,outside) static 2.2.1.2

object network SecondaryServer

host 192.168.1.3

nat (inside,outside) static 2.2.1.3

object network PrimaryServer-ext

host 2.2.1.2

object network SecondaryServer-ext

host 2.2.1.3

nat (inside,inside) source dynamic any interface destination static PrimaryServer-ext PrimaryServer

nat (inside,inside) source dynamic any interface destination static SecondaryServer-ext SecondaryServer

Me