Static vs. Dynamic DNS
An IP address is a number that anyone in the world can use to connect to
your server. An IP address is usually shown as four numbers separated by
dots: 184.108.40.206 (example.com) or 127.0.0.1 (your local machine, localhost ).
Your ISP probably changes your IP address every so often; you aren't guaran-
teed to get a the same IP address each day unless you pay extra for a static
IP . If you knew to ask for a static IP, you probably already know how to set
up a domain name and DNS server to point to your machine (if not, and you
want a static IP, check out the end of Appendix 4, How to Install a Cloud
Server , on page 229 ).
But you don't need a static IP for your friends to find you. There's a trick that
lets you use your changing, dynamic IP just as easily.
First off, if you don't know what your IP even looks like, point your browser
And that's what your IP looks like to the outside world.
If that changes every few hours or every few days, that can be annoying, as
you have to keep telling your friends what IP address to use to connect to
you. But you're in luck! You can get set up with a dynamic DNS registration
They'll get you set up so that your friends can use a friendly name to find you
on the Internet—something like andyminecraft.dns.org .
Now that they can find your machine, you need to let them in.
Open Up Your Firewall
Windows, Mac, and Linux machines, as well as your cable modem or ISP's
router, can all run firewall software, which is designed to block exactly what
we're trying to accomplish here. The idea is that twisted, evil griefers are
always trying to attack your machine and break in. So most machines run
some kind of firewall to lock out every port except the ones you really want
to have open and are expecting.
So first you need to make sure your computer is open to port 25565. How
you do this depends on the operating system you are running.