Digital Anvil does not recommend running a server and client on the same machine. Both pull resources from the CPU and RAM. Having a low ping connecting to your own server is normal.

I run both on my machine, but when there's a lot fo people on my server, I really can play myself due to limitations of my CPU so I just let others play and wait until the numbers drop down a bit.

As far as others having problems connect to you, it could be a couple of reasons. Firewall, NAT, router just to mention a few.

Since your server is REALLY REALLY close to your client, it won't take very long for your Ping requests to be returned (usually about 0 seconds).

Ping is an indication of several factors combined: server quality, distance from server, and network congestion. It tells you how long it takes packets to get back and forth (in milliseconds).

Please don't create servers on machines you don't intend to dedicate to the cause. It'll run very quickly for you, and very slowly for everyone else. If you can't run a decent server, don't run one at all. Right now, the net is flooded with bad FL servers.