Let's say that you have the domain name mydomain.com. You currently have a Minecraft server running at 1.2.3.4, port 28000, and have an "A" record already set up pointing subdomain mc to that IP -- meaning that clients can connect to mc.mydomain.com:28000 and join the server. But, it would be easier if they could connect to just mc.mydomain.com and leave off the port. Here's how you could accomplish that:
- Visit the Domains page in your control panel.
- Under the "mydomain.com" domain, click the empty Subdomain field at the bottom.
- Enter _minecraft._tcp.mc.
- Select "SRV" from the drop-down menu for the new subdomain.
- Click the empty Target field for the new subdomain.
- Enter mc.mydomain.com:28000.
- At the bottom of the page, click "Submit changes".
- Wait a minute or so for the change to take effect.
You could also make it so the bare mydomain.com works. To do this, enter _minecraft._tcp instead of _minecraft._tcp.mc as the SRV subdomain. If you have a website at mydomain.com, it will continue to work when you do this, because only Minecraft will look for the special _minecraft._tcp SRV entry.
With TeamSpeak3, the same procedure applies, except that you'd begin the subdomain with _ts3._udp instead of _minecraft._tcp.