Redirecting Subdomain to specific Port via DNS

Use case: Hosting multiple minecraft servers on one Server with the same IP.

Therefore you can use SRV-records:

Add a DNS record with the following scheme to at your DNS: 

_service._proto.name. TTL class SRV priority weight port target

For example this can look like this: 

_minecraft._tcp.sub1. 86400 IN SRV 0 5 5060 sub1.example.com
The service for which you are trying to set up this type of DNS records must support those! (for example Minecraft does)

Some other examples from stackoverflow: 

_minecraft._tcp.arboristal.com. 86400 IN SRV 10 40 25565 mc.arboristal.com.
_minecraft._tcp.arboristal.com. 86400 IN SRV 10 30 25566 tekkit.arboristal.com.
_minecraft._tcp.arboristal.com. 86400 IN SRV 10 30 25567 pvp.arboristal.com.

Sourced partially from stackoverflow.com - Redirect DNS to different ports