So what is hairpinning, anyway? Hairpinning is when traffic received on an interface is immediately routed back out the same interface. If you visualize the packet flow, it looks something like a hairpin:
The command "same-security-traffic permit intra-interface" allows us to hairpin traffic on an ASA. The most common use case is allowing remote access VPN traffic to traverse a site to site VPN tunnel as shown in the diagram above.
However, since we have the ability to hairpin VPN traffic, it seems safe to assume that we can hairpin other traffic as well.
Let’s look at the following scenario: