hairpin NAT
jargonnetworking
Reaching your own public address from inside your own network - the traffic goes out to the NAT and hairpins straight back in.
Without hairpin (loopback) NAT support, an internal client asking for the company's public IP gets nowhere, which is why split-horizon DNS often answers with the internal address instead. The name is the shape the traffic draws: out, U-turn, back.
Also known as: NAT loopback, hairpinning, NAT hairpinning