I just figured out how to port forward, and created a bukkit server in 1.7.2 that my friend can get on to (1.7.4 profile) from an external IP. A few minutes ago, it failed to bind port, but I fixed it to a 25566 port. Now when I try to use my internal address on any version, with and without the 25566 port, minecraft closes and goes back to the start menu. My friend is having no problems either. Please help! Thanks!
Server properties:
#Minecraft server properties
#Thu Jan 02 23:32:57 EST 2014
generator-settings=
op-permission-level=4
allow-nether=true
level-name=world
enable-query=false
allow-flight=false
announce-player-achievements=true
server-port=25566
level-type=DEFAULT
enable-rcon=false
level-seed=
force-gamemode=false
server-ip=192.168.0.17
max-build-height=256
spawn-npcs=true
white-list=false
spawn-animals=true
hardcore=false
snooper-enabled=true
online-mode=true
resource-pack=
pvp=true
difficulty=1
enable-command-block=false
gamemode=0
player-idle-timeout=0
max-players=20
spawn-monsters=true
generate-structures=true
view-distance=10
spawn-protection=16
motd=A Minecraft Server
Added (1). On the server log, it says Internal exception: java.io.ioexception: An existing connection was forcibly closed by the remote host
Added (2). It is now crashing when I try to join any server