Port theory, Port Map software and Minecraft

Paul P · 08-01-2012, 03:04 AM

Hello all

both my son and I use Macs, he being on Leopard 10.5.8 with all updates, and me on Snow Leopard 10.6.8 with all updates. My son has recently expressed a desire to set up a server for Minecraft, so that he can invite his school friends to play. His reading on the internet suggested that a software called Port Map would help.

Unfortunately my knowledge of "Port Theory" is nil, so I cannot help him at all.

I am just wondering if anyone out there could help me with this issue ? Some things to consider :

1. I have a wired Ethernet router, directly connected to my computer, which connects to the internet, and my son piggy backs off this router by connecting an ethernet cable form his computer to one of the router's ports.

2. As my internet needs have always been simple, I have always had the "allow only essential services" checked in the firewall section of the OS X Security preference pane. I need to uncheck this to get Mac Port to recognise the router, which makes me a little uncomfortable.

3. I have no idea where to even start with Port map software, as I don't understand port theory at all. Any suggested settings, or attempts to explain this, would be most appreciated.

4. Do my son's friends need Port Map as well ? They are mixed Windows and Mac users.

Thanks to all in advance.

SirDice · 08-01-2012, 03:37 AM

Besides IP addresses there are also "ports". Each port has a specific function although this is not set in stone. Port 80 for example is used for HTTP (webtraffic) and port 25 is SMTP (email).

A "service" has a port listening for incoming connections. The "service" can be a webserver, an email-server or a game server. In order for the service to be accessible, its port will need to be accessible.

Your ethernet router translates your local, private IP addresses to your internet address. In order for a service to be available your router must be configured to "port forward" the incoming connection. All this "port forwarding" does is route the incoming connection to a specific IP address and port behind the router making the service that's listening on that port accessible from the internet.

In short, consult the manual for your router, consult the game manual to see which port needs to be forwarded and configure your ethernet router.

Paul P · 08-01-2012, 03:51 AM

Thanks.

Without wanting to appear thick or lazy, I'm not sure if your response will really help me. I need help at the Port Theory 101 level, and also some help with understanding why I would choose certain settings over others. For example, if you were trying to achieve what I am trying to, what settings would you use in Port Map, or in your Security Preference Pane, and why ?

Thanks

SirDice · 08-01-2012, 04:13 AM

None, as the setting doesn't need to be done on your machine. Only your ethernet router needs to be configured. And perhaps your son's machine.

acme.mail.order · 08-01-2012, 07:55 AM

There's two "ports" to deal with - the one on the back of the router and the one relating to the internet. We are dealing exclusively with the second one here.

You need to understand two things: IP addresses and ports. Picture your computer as an apartment building. Your IP address would be your street address. There may be more than one building (computer) in the complex (local network). Ports are the apartments, each containing a different service (web, email, Minecraft etc.). So a delivery needs both an address and an apartment number.

Like the doorman, your router decides which building (computer) the service lives in, and sends deliveries to that apartment. The mailman doesn't know about this, he drops the package off at the front door (router) and lets the building staff take care of it from there.

Complication: The building complex is on a barge and occasionally moves to a different part of the river, thus getting a new address.

You need to do the following:

Configure your network (each computer) to use fixed IP addresses rather than "DHCP". Read your router's manual for details, but the IP address you must set (by hand) will look like 192.168.1.X or 192.168.0.X.

Tell your router to forward the Minecraft port (25565) to whichever computer is running the server.

You can find out your IP address at http://checkip.dyndns.org/ . You can test your setup by calling someone outside your house and asking them to try to connect to this address. No, you can't test it from inside your house - you must be in a different place.

Check your IP address regularly - like 3-4 times a day for a week. If it changes often we have to do more work.

trevor · 08-01-2012, 06:53 PM

Brilliant explanation of ports, acme! Nice work making a complicated subject understandable!

Paul, I'll try to answer your questions one by one.

Quote:

Originally Posted by Paul P


	1. I have a wired Ethernet router, directly connected to my computer, which connects to the internet, and my son piggy backs off this router by connecting an ethernet cable form his computer to one of the router's ports.

That's a very standard setup. No worries.

Quote:

Originally Posted by Paul P


	2. As my internet needs have always been simple, I have always had the "allow only essential services" checked in the firewall section of the OS X Security preference pane. I need to uncheck this to get Mac Port to recognise the router, which makes me a little uncomfortable.

You don't need to do anything at all on your computer. Leave the firewall on your computer alone--your computer is not going to be a Minecraft server, so doesn't need to be changed in any way at all.

Quote:

Originally Posted by Paul P


	3. I have no idea where to even start with Port map software, as I don't understand port theory at all. Any suggested settings, or attempts to explain this, would be most appreciated.

On your son's computer, you'll need to allow contact from outside on the Minecraft port, so set Minecraft to "Allow All Incoming Connections" in System Preferences > Security > Firewall tab.

Then give your son's computer a static IP address in it's current subnet. For example, if the computers in your house use the range of IPs from 10.10.10.0 to 10.10.10.255, then give your son's computer a static IP of, say, 10.10.10.250, assuming that nothing else is using that IP.

If the computers in your house use the range of IPs from 192.168.1.0 to 192.168.1.255, then maybe give your son's computer an IP of 192.168.1.250.

Static IPs are given in System Preferences > Network > Configure IPv4: set it to "Manually". Then type in the static IP address immediately below that, next to "IP Address:". (I'm not on a computer running Leopard right now, and my memory isn't perfect. There might be a couple more steps in getting to the right place in Leopard, for example you may have to click the TCP/IP tab, or similar.) Subnet Mask is usually 255.255.255.0, unless you have really unusual requirements.

Now, on the router, there will be something in the configuration pages about Port Forwarding. Tell your router, using it's configuration pages, to port forward everything that it gets on it's external interface on port 25565/TCP to go to the same port at the static IP that you gave to your son's computer.

Quote:

Originally Posted by Paul P


	4. Do my son's friends need Port Map as well ? They are mixed Windows and Mac users.

No. Nobody needs Port Map. Forget anything anyone has ever told you about Port Map. Your son's friends will either need to connect to the external IP address of your router, which you can find using, for example, http://whatismyip.com or many other places. If you change IP often, then you should set up a domain name. You can get one for free-ish at http://dyndns.org (expect a monthly hassle, though) and you'll need to set up your router to communicate with dyndns.org when your IP changes.

Trevor

Paul P · 08-14-2012, 04:30 AM

Hello Trevor and acme,

apologies to both of you for my delayed reply. It's been a cold winter over here (by our standards) and I've been dealing with an assortment of family ailments. I usually respond to this sort of help right away.

Acme, I appreciate your theoretical attempt to explain all this to me.

Trevor, your post was amazing and way beyond anything I could have expected. Just like having tech support next to you holding your hand.

Well, I have set up everything just like you said (at least I think I have), but amazingly, my son has not tested it yet. Initially, he wasn't able to get a hold of his friend, and when he did, his friend installed a new version of Minecraft, which dosen't work, or some such. My son has also discovered a new way of setting up a server called craftbukkit. I don't know anything about this. At any rate, as soon as we can, we will test it and report back.

Trevor - Sir, I salute you.

Thanks
Paul

08-01-2012, 03:04 AM	#1
Paul P Triple-A Player Join Date: Mar 2007 Location: Sydney Australia Posts: 94	Port theory, Port Map software and Minecraft Hello all both my son and I use Macs, he being on Leopard 10.5.8 with all updates, and me on Snow Leopard 10.6.8 with all updates. My son has recently expressed a desire to set up a server for Minecraft, so that he can invite his school friends to play. His reading on the internet suggested that a software called Port Map would help. Unfortunately my knowledge of "Port Theory" is nil, so I cannot help him at all. I am just wondering if anyone out there could help me with this issue ? Some things to consider : 1. I have a wired Ethernet router, directly connected to my computer, which connects to the internet, and my son piggy backs off this router by connecting an ethernet cable form his computer to one of the router's ports. 2. As my internet needs have always been simple, I have always had the "allow only essential services" checked in the firewall section of the OS X Security preference pane. I need to uncheck this to get Mac Port to recognise the router, which makes me a little uncomfortable. 3. I have no idea where to even start with Port map software, as I don't understand port theory at all. Any suggested settings, or attempts to explain this, would be most appreciated. 4. Do my son's friends need Port Map as well ? They are mixed Windows and Mac users. Thanks to all in advance. Last edited by Paul P; 08-01-2012 at 03:13 AM.

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08-01-2012, 03:37 AM	#2
SirDice MVP Join Date: Aug 2009 Posts: 1,119	Besides IP addresses there are also "ports". Each port has a specific function although this is not set in stone. Port 80 for example is used for HTTP (webtraffic) and port 25 is SMTP (email). A "service" has a port listening for incoming connections. The "service" can be a webserver, an email-server or a game server. In order for the service to be accessible, its port will need to be accessible. Your ethernet router translates your local, private IP addresses to your internet address. In order for a service to be available your router must be configured to "port forward" the incoming connection. All this "port forwarding" does is route the incoming connection to a specific IP address and port behind the router making the service that's listening on that port accessible from the internet. In short, consult the manual for your router, consult the game manual to see which port needs to be forwarded and configure your ethernet router.

08-01-2012, 03:51 AM	#3
Paul P Triple-A Player Join Date: Mar 2007 Location: Sydney Australia Posts: 94	Thanks. Without wanting to appear thick or lazy, I'm not sure if your response will really help me. I need help at the Port Theory 101 level, and also some help with understanding why I would choose certain settings over others. For example, if you were trying to achieve what I am trying to, what settings would you use in Port Map, or in your Security Preference Pane, and why ? Thanks

08-01-2012, 04:13 AM	#4
SirDice MVP Join Date: Aug 2009 Posts: 1,119	None, as the setting doesn't need to be done on your machine. Only your ethernet router needs to be configured. And perhaps your son's machine.

08-01-2012, 07:55 AM	#5
acme.mail.order League Commissioner Join Date: Sep 2003 Location: Tokyo Posts: 6,045	There's two "ports" to deal with - the one on the back of the router and the one relating to the internet. We are dealing exclusively with the second one here. You need to understand two things: IP addresses and ports. Picture your computer as an apartment building. Your IP address would be your street address. There may be more than one building (computer) in the complex (local network). Ports are the apartments, each containing a different service (web, email, Minecraft etc.). So a delivery needs both an address and an apartment number. Like the doorman, your router decides which building (computer) the service lives in, and sends deliveries to that apartment. The mailman doesn't know about this, he drops the package off at the front door (router) and lets the building staff take care of it from there. Complication: The building complex is on a barge and occasionally moves to a different part of the river, thus getting a new address. You need to do the following: Configure your network (each computer) to use fixed IP addresses rather than "DHCP". Read your router's manual for details, but the IP address you must set (by hand) will look like 192.168.1.X or 192.168.0.X. Tell your router to forward the Minecraft port (25565) to whichever computer is running the server. You can find out your IP address at http://checkip.dyndns.org/ . You can test your setup by calling someone outside your house and asking them to try to connect to this address. No, you can't test it from inside your house - you must be in a different place. Check your IP address regularly - like 3-4 times a day for a week. If it changes often we have to do more work.

08-14-2012, 04:30 AM	#7
Paul P Triple-A Player Join Date: Mar 2007 Location: Sydney Australia Posts: 94	Hello Trevor and acme, apologies to both of you for my delayed reply. It's been a cold winter over here (by our standards) and I've been dealing with an assortment of family ailments. I usually respond to this sort of help right away. Acme, I appreciate your theoretical attempt to explain all this to me. Trevor, your post was amazing and way beyond anything I could have expected. Just like having tech support next to you holding your hand. Well, I have set up everything just like you said (at least I think I have), but amazingly, my son has not tested it yet. Initially, he wasn't able to get a hold of his friend, and when he did, his friend installed a new version of Minecraft, which dosen't work, or some such. My son has also discovered a new way of setting up a server called craftbukkit. I don't know anything about this. At any rate, as soon as we can, we will test it and report back. Trevor - Sir, I salute you. Thanks Paul