Can Anyone explain me what these Steam Port used for ?

[⎛⎝DeViLMaN666⎠⎞]

So i just bought Castle Crasher and i cant use voice and host a game since i need to open these port but im wondering do i need to open them all ? what they used for ?

https://support.steampowered.com/kb_article.php?ref=8571-GLVN-8711

Your network must be configured to allow Steam access to the following ports (in order from highest to lowest priority for QoS users):

Steam Client
UDP 27000 to 27015 inclusive (Game client traffic)
UDP 27015 to 27030 inclusive (Typically Matchmaking and HLTV)
TCP 27014 to 27050 inclusive (Steam downloads)
UDP 4380



Dedicated or Listen Servers
TCP 27015 (SRCDS Rcon port)



Steamworks P2P Networking and Steam Voice Chat
UDP 3478 (Outbound)
UDP 4379 (Outbound)
UDP 4380 (Outbound)