Networking - the answer to...

How can I fly together with other X-Plane users?

How can I run X-Plane with multiple monitors?

How can I interface X-Plane to my own software or equipment?
X-Plane uses TCP/IP networking for all external interactions. You need to get your computer set up in a TCP/IP network, and then get X-Plane set up to communicate with its partners over the network. If your computers are already set up for TCP/IP networking, skip down to the X-Plane setup.

Can I network between Macintosh and Windows?

Yes! The networking protocol is platform-independent.

However...

As of V9.0, PowerPC and Intel computers cannot be networked because of their opposite byte order used for numerical values. (Intel Mac can network with Intel PC.) In previous X-Plane versions the networking code did the byte order translation. This logic was removed in V9. The author is the owner of a perfectly decent G5 Macintosh and is now unable to network with most other computers. As a result, the remainder of this page is frozen at V8.x and is somewhat stale.

How do I set up TCP/IP networking on my computer?

The general answer to this question is too varied and complex to include in the FAQ. For step by step instructions on how to set up a private local network, see the description below.

How do I set up X-Plane for networking?

    Assuming your computer has TCP/IP networking set up, here's what you need to do in X-Plane. Note the format of X-Plane's networking control panel has changed over time. This description applies to X-Plane 8.32.
     
    1. Start up X-Plane on the computers you have networked.
    2. On each computer, open the Settings -> Data Input & Output menu.
    3. Select either the INET1 or INET2 tab. INET1 has the settings for multi-player use; INET2 has settings for other networking applications (multi-head display, instructor console, etc.)
    4. In the top panel, you should see in white the IP address you've set up on your computer. (If you didn't set up your own networking, you should see some IP address. If the address you see is 127.0.0.1, TCP/IP networking is not set up on your machine. Go back and try again.)
    5. Click the selection button next to the networking option(s) you want to enable. You'll get a window next to it; enter the IP address of the computer that corresponds to that option. Remember you're defining the role of the other computer here. For example, if you're configuring the master computer of a three-view setup, in the INET2 tab click two of the "IP address of extra visual..." options and enter the IP address of each machine to the far left. The second window indicates "49000", the port number X-Plane normally uses. In most cases, leave this alone.
    6. Do this on all the computers, selecting the appropriate options. There are three choices for the additional views of a multi-screen setup (each one labeled IP Address of Master Machine):
    7. After a short time,you should see a status message at the bottom of each screen indicating that it is getting network messages from the other machine(s). Machines that are slaves (i.e., extra visuals) should see very frequent updates. Master machines should see a reply from the extra visuals every several seconds or so.
    8. Now close the Data Input & Output menu on each machine, and you're ready to go.
Note!!
  1. If you're running firewall software on your computer, you need to enable communications on port 49000 (or whatever port you're using for X-Plane).

  2. If your machine has multiple network adaptors (like wired and wireless), X-Plane may not report the correct network address. X-plane may also not report the network address and/or give you an error message when you open the networking menu if you have a local firewall configured. You'll have to go to your operating system's networking control panel and check the settings for the adaptor you're using to find the correct address. (Thanks to Bob Feaver.)

  3. If you have a French keyboard you will not be able to enter the number 6 because X-Plane pre-empts the use of that key. Switch the keyboard temporarily to English language and it will work. (Thanks to Daniel Leygnat for this tidbit.)

What if I'm behind a router/firewall?

So let's say you want to do formation flying with someone else on the internet, and you have a cable modem or DSL and you have a firewall router. [Personally, I think anyone who connects a computer, especially a Windows machine, directly to the net without a firewall needs their head examined, but I digress...]

This gets a little more complicated, because the TCP/IP address X-Plane sees is the address assigned to your computer, not the address your router presents to the internet. Also, the person on the other end can only see your router, not the machine running X-Plane. Both these problems need to be fixed using your router's management pages. These are going to look different for different makes and models of routers. For instructions for different makes and models of routers, see the Port Forwarding Help page.

I have a Linksys WRT-54G, which is pretty popular in these parts, and I'll go through the steps, describing generically what's going on. Check the documentation for your router and you should find similar functions.
  1. Fire up a web browser and connect to your router. The Linksys is normally at 192.168.1.1 - just type that into the browser address bar and hit return. You should get a window with a username and password prompt. Enter the admin password for your router.

  2. Find the external IP address of your router. On the WRT-54G, click the Status tab and then the Router subtab. Anyway, somewhere you should find a page that tells you the IP address your ISP has assigned you. (The page might be labeled Internet or Wide Area Network.)

    This is the address you give to the other folks you're networking with - not the IP address of your computer.

  3. Set up port forwarding. On the WRT-54G, click the Applications and Gaming tab and then the Port Range Forward subtab. (Again, on other routers, look for a similarly named page.)  This should give you a table. Fill in a table row with a port number of 49000 (same value for Start and End if you can give a range), select either UDP or BOTH for the protocol, and enter the IP address of your computer (the one X-Plane is telling you or that you got from your computer's network configuration). Make sure the Enable box is checked if there is one. If there's an Application or Name entry, enter X-Plane. (This is optional and is just for your own information.) Click the OK or Apply or Save button to change the router settings.
That should do it. If the folks on the other end do the same and you get their external IP addresses set up right in your X-Plane's INET1 screen, you should start seeing connections.

How do I communicate with X-Plane with my own software?

You can communicate directly with X-Plane's UDP (networking protocol). Roy Coates maintains a web site with a lot of reference material and several useful utilities.

You can write plug-ins, which are loadable pieces of software that run as part of the X-Plane application. Ben Supnik maintains a web site for plug-in development.

Warning: The content and format of X-Plane's UDP messages tends to change from version to version. The X-Plane developer community recommends for most applications that you build a plug-in and handle your own network communications. The plug-in interface is stable and does not require you to track version to version changes (unless you want to take advantage of new features).

How do I set up TCP/IP networking on my computer?

The general answer to this question is too varied and complex to include in the FAQ. How you set up your computer for networking depends completely on your environment - what kind of equipment you have and what kind of network you're connected to. If you're networking from home through the internet, you should already be set up with your ISP (Internet Services Provider). If you're in an office environment, consult with your office network manager.

Warning!! Before you tinker with the networking setup on your computer, make sure you know what you're doing. Screw up your networking and you'll screw up other operations on your computer. Worse, in environments like office networks, you can also screw up the operations of many other people and get yourself in considerable hot water with the folks in charge.

If you have a couple of computers sitting about and the necessary ethernet equipment, read on...

The following discussion applies to setting up networking using a direct-wired connection or a network hub or switch. These configurations are becoming less common - most home networks are built around a firewall router. If you have a router, use your computer's default network setup (obtaining a network address automatically from the router).

How do I set up a private LAN?

Any computer recent enough to run current versions X-Plane should have twisted-pair ethernet. The cable connectors look like oversize modular phone gear, with 8 contacts instead of 4 or 6.

The minimum equipment you need to plug two computers together is a cross-over cable. Just plug the cable into the ethernet ports on the two computers. Cross-over cables are a bit uncommon; ask for one by name. In rare cases you may have trouble getting one or the other computer to recognize that it has a LAN connection. If one machine is giving you trouble, try powering up the other one first.

If you're having trouble with the cross-over cable, or if you're trying to network more than two computers, get an ethernet hub or switch and a set of straight-through cables. Connect each computer's ethernet port to a port on the hub with a straight-through cable. Power up the hub before powering up the computers. This is the preferred form of network wiring. If you ask for a twisted-pair ethernet cable at the computer store you'll get a straight-through cable by default.

I've been told that present day network adaptors automatically sense what kind of cable you're using, so it should be possible to connect two computers directly with a straight-through cable. I haven't tried it myself...

How do I tell a straight-through cable from a cross-over cable?

Take the two ends of the cable and hold the connectors side by side, facing in the same direction. (And the same side up!) The connector bodies should be transparent just below the contacts. (If they're not, you're pretty much screwed unless you're handy with a continuity tester.) The wires are color-coded, and you should be able to see the wires just behind the connector pins. Half the wires have solid colors and the other half are striped; the striped ones may look white depending on how the stripes are oriented.

Anyway... if the colors on the wires are arranged the same way when you look at the connectors side by side, it's a straight-through cable. If the colors are arranged in mirror image, it's a cross-over cable.

How do I set up networking on a private LAN (Macintosh)?

     
    1. Open System Preferences and select Network.
    2. In the second pull-down, select Built-in Ethernet (or Airport if you're running wireless).
    3. Click the lock and authenticate if necessary to enable changes
    4. For "Configure IPv4", select "Manually".
    5. For "IP Address", enter four numbers, each from 2 through 254, separated by dots. (For example, "123.32.100.45". Don't use 0, 1, or 255 values.)
    6. For "Subnet Mask", enter "255.255.255.0".
    7. Make sure the other fields are blank.
    8. Click Apply Now.
    9. Close the System Preferences panel.
    10. On the other computer(s), do the same, using a different IP address. The first three numbers must be the same; only change the fourth.

How do I set up networking on a private LAN (Windows)?

    1. Open Start -> Settings -> Control Panel.
    2. Open Network and Dialup Connections. (Other Windows versions may just call it Network.)
    3. Double-click Local Area Connection or whatever entry corresponds to the LAN adaptor you're using. (If you can't find a suitable LAN adaptor entry, you don't have one configured. Solving this will be way more complicated than I can deal with here.)
    4. Double-click Internet Protocol (TCP/IP). (On older Windows versions these two panels may be combined in one. Find the TCP/IP entry under your LAN adaptor.)
    5. Select "Use the following IP address".
    6. For "IP Address", enter four numbers, each from 2 through 254, separated by dots. (For example, "123.32.100.45". Don't use 0, 1, or 255 values.)
    7. For "Subnet Mask", enter "255.255.255.0".
    8. Leave the other fields blank.
    9. Click OK to close the various control panels. You will have to reboot the PC to get the new settings to take effect.
    10. On the other computer(s), do the same, using a different IP address. The first three numbers must be the same; only change the fourth.


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