I'm working on a C# application which connects to a MySql database residing on a computer on our local network. However, later on, our website will also connect to that database sometimes, so I have a port forwarding for Internet traffic to that database. But for some reason, connecting using the local IP address 192.168.1.1 is slower than connecting using the Internet IP address 70.28.---.---. It's not really a big issue, but I'm just confused since I thought it would be the other way around.
This sounds like a routing / networking issue but there isn't enough detail in the question to make this a definite answer.
What would be useful for this would be a diagram of routers and networks, as well as routing tables for the hosts involved, that makes it clear which way packets go. (feel free to anonymize network identifiers, e.g. use A.B.C.D and E.F.G.H as IP addresses)
Also, see if you get a similar performance difference using ping or other common network tools with lower overhead than a database (e.g. HTTP server, ssh, etc. for getting an idea of TCP performance). If not, I'd look inside the database for the issue.