Im using my blackberry as a modem, and connecting it to my computer (obviously). but i have internet sharing on and connect directly to my xbox 360 to play live, how can i change my NAT settings to open by doing this without using a router?

The MTU or maximum transfer unit is configurable at the
modem that is bringing the internet service, in your case the Thomson tg782t modem, do not attempt to change the registry

I am not that much clear whether you can change your Ip adress, but any queries regarding Ip-detais can be solved here, http://www.ip-details.com/

You Will Have to Disable the Firewall In Your modem / Router

And IF it is a router then Open The Ports

• TCP 80
• UDP 88
• UDP 3074
• TCP 3074
• UDP 53
• TCP 53

Hello Brian

Using Xbox Live on Dial up Modem would be a big pain, still listing the steps for you, hope you have a stable connection to successfully connect

Required Items

- Windows ME, XP, Vista
- PC with dial-up connection working
- Ethernet Cable (RJ45) cable or CROSSOVER CABLE
- Xbox 360

Let's Get Started

1. First connect the Xbox 360 and the PC using the Ethernet cable.
2. Double Click your Dial-up Network connection and wait for it to connect.
3. Choose "Start Menu" and then choose "Settings" then "Control Panel".
4. Select "Network and Internet Connections".
5. Open the "Network Setup Wizard" and then press "Next".
6. On the next screen Ignore the checklist and press "Next" again.
7. Select "This Computer connects directly to the internet." and press "Next".
8. Now Select your dial-up internet connection as your default connection to the Internet and press "Next".
9. Select "Local Area Connection" as your private connection and leave all other areas untouched and click "Next".
10. On the Workgroup screen leave all settings alone and click the "Next" button.
11. On the next screen Turn on "File and Printer Sharing" if you want to share your files, mp3's, divx files with your xbox 360 and click "Next".
12. Now review the settings and click "Next" to apply the changes.
13. You do not need to run the Network Setup Wizard on any other pc's so just click "Next" and continue.
Now that the wizard has completed you may need to reboot your PC and dial your internet connection again.
Xbox 360 Setup

Now we have configured your PC to share its internet connection and files to your Xbox 360 we need to configure the Xbox 360.

(Steps for old Xbox 360 Dashboard, in case you do not have NXE dashboard)

1. Go to the "Xbox 360 Dashboard".
2. Select the "System" Blade.
3. Select the "Network Settings" Option
4. Now choose "Test Xbox LIVE Connection".

Your Xbox 360 will now attempt to contact your home network. It will check to make sure it can assign itself a IP ADDRESS from your PC and then it will also check DNS server information and XBOX LIVE.
let me know if this helps

Yes, but if you want to connect the X-box and computer directly you may need to get a crossover cable. Sorry, I can't say for sure on this as it depends on the network card in the PC.

You should have a box in the configuration dialog for the Cricket saying something like "Allow other network users to connect through this computers internet connection". Be sure this box is checked.

USB to PC is fine, make sure you have the original installation disk for it. Then you can connect the Xbox via network cable. There shouldn't be any problem as your modem can take 2 connections by the sound of it.

you are only sharing files with your pc to xbox, you cannot connect to the net throught the pc, the xbox has to have connection to a modem/router, or a router itself which is connected to modem.

none at all.

Shared connection with a modem and a router
1. Turn the modem off, and then turn it back on. Then turn the router power off, and then turn it back on. This is also known as power cycling the modem and the router.

Power cycle the modem first, and then power cycle the router. To power cycle these devices, you should follow your manufacturer’s specific instructions. Here are some general steps:
a. Remove the power supply from your device.
b. Leave the device unplugged for 15 to 30 seconds.
c. Reattach the power supply to the modem by following the device manufacturer’s instructions.
d. Wait several minutes for the device to start and to establish a connection with your broadband provider.
e. Verify that the modem shows the appropriate power and Internet connection indicator lights by following the manufacturer’s instructions.
2. If power cycling your modem and router does not resolve the problem, try connecting the Xbox 360 console to Xbox LIVE by using the modem only. This eliminates any configuration problems on the router. If this setup works without the router, there is probably a configuration issue with the router. See the manufacturer’s documentation that is included with the router or contact the technical support group for the router.
3. Verify that your router's Dynamic Host Configuration Protocol (DHCP) service has been enabled. DHCP enables the router to assign IP addresses to the computers and consoles on your network when you go online. If you need help with this, see the manufacturer’s documentation that is included with the router or contact the technical support group for the router.
4. If you manually entered an IP address, gateway, subnet mask and/or DNS servers in the Network Settings area of the Xbox Dashboard , verify that it they are correct. At this point, you can also set your IP settings to Automatic. To do this, follow these steps:
a. Move to the System area.
b. Select Network Settings.
c. Select Automatic.
5. If your ISP requires Point-to-Point Protocol over Ethernet (PPPoE) settings, try connecting to only the modem after you enter these settings in the Network Settings area of the Xbox Dashboard. Network Settings area of the Xbox Dashboard.

Note Some ISPs may require Point-to-Point Protocol over Ethernet (http://www.xbox.com/en-US/support/connecttolive/xbox360/resources/glossary.htm#ethernet) (PPPoE) settings, This means that you may need settings such as a username and password in order to gain access to your ISP’s network. If you are unsure whether you have to enter these settings, please contact your ISP support group. At this point, if you can connect directly to the modem, see your router documentation to configure the PPPoE settings correctly on the router.
6. If you are receiving an IP conflict error in the More Info section of the Xbox Dashboard, turn off all devices on the network. Try to connect to Xbox LIVE with only the modem and Xbox 360 console connected.

If this works, there may be a configuration issue on the router’s Dynamic Host Configuration Protocol (DHCP) server. DHCP enables the router to assign temporary IP addresses to the computers on your network when you go online. If you need help with understanding DHCP or the configuration, see the manufacturer’s documentation that is included with the router or contact the technical support group for the router.
Shared connection with a gateway device (combined modem and router)
1. Make sure that the gateway is turned on. A gateway integrates a high-speed Internet modem with a router.
2. Verify that there is network activity by looking for the sequence of blinking lights on your gateway that generally indicate Wide Area Network (WAN), Local Area Network (LAN), and connected power status.
Note These names will vary from model to model.
3. Turn the gateway device off, and then turn it back on. This is also known as power cycling the gateway. To power cycle this device, you should follow your manufacturer’s specific instructions. Here are some general steps:
a. Remove the power supply from your device.
b. Leave the device unplugged for 15 to 30 seconds.
c. Reattach the power supply to the gateway by following the device manufacturer’s instructions.
d. Wait for the device to start and to establish a connection with your broadband provider.
e. Verify that the gateway shows the appropriate power and Internet connection indicator lights by following the manufacturer’s instructions.
4. The IP address that you entered in to the Network Settings area of the Xbox Dashboard may be incorrect. Be sure that this address is correct, or set your IP settings to Automatic in the Xbox Dashboard.
5. If you are receiving an IP conflict error in the More Info section of the Xbox Dashboard, turn off all devices on the network. Try to connect to Xbox LIVE with only the modem and Xbox 360 console connected.

If this works, there may be a configuration issue on the router’s Dynamic Host Configuration Protocol (DHCP) server. DHCP enables the router to assign temporary IP addresses to the computers on your network when you go online. If you need help with understanding DHCP or the configuration, see the manufacturer’s documentation that is included with the router or contact the technical support group for the router.
Shared connection with Microsoft Windows Internet Connection Sharing
Shared connection with Microsoft Windows Internet Connection Sharing
1. Verify that you can surf the Internet from your PC. If you cannot surf the Internet, there is probably a problem with your Internet connection. Contact your ISP for support.

If you are using a USB modem to connect to the Internet, the modem will be listed in the "Dial-up" window as the connecter that you are sharing and that you have configured. To verify that Internet Connection Sharing configured it correctly, use the following steps:
a. Click Start, and then click Control Panel.
b. In Control Panel, double-click Network Connections.
c. Right-click your broadband connection, and then click Properties.
d. In the Properties dialog box, click the Advanced tab.
e. Click to select the Allow other users to connect through this computer’s internet connection check box.
f. Click OK.
Ethernet Properties
2. Power cycle the modem. If the modem does not have an on and off switch, unplug the modem from the power outlet. You cannot follow this step if you are using a USB modem. Instead, go to the next step. You must follow this step if you are switching the modem between the Xbox 360 console and a computer.
3. On the computer, click Start, click Run, type ncpa.cpl, and then click OK.
4. On the View menu, click Tiles.
5. If the connection is listed as Firewalled, the firewall may have to be configured. See your firewall documentation.
6. Enter manual settings in the Xbox 360 Dashboard for IP address, subnet mask, DNS address and gateway and test the connection: To edit the settings:
a. In the Xbox 360 dashboard, move to the System section.
b. Select Network Settings.
c. Select Edit Settings.
d. Enter the following:
• IP Address : 192.168.0.2
• Subnet mask : 255.255.255.0
• Default Gateway : 192.168.0.1
• DNS server (Primary): 192.168.0.1
• DNS server (Secondary): 192.168.0.1Xbox 360: Test Xbox LIVE connection fails at IP address

THINGS TO TRY loadTOCNode(1, 'whattotry'); Direct connection with a modem only loadTOCNode(3, 'whattotry'); 1. If you are connecting to Xbox Live by using a modem that is connected directly into your broadband socket, your IP address settings are obtained from your ISP. Set your IP address in Network Settings to Automatic. 2. If you use a static IP address that you obtained from your ISP, you must manually enter this address in the Dashboard. Contact your ISP for their static IP address if you do not know it. If the IP is not static, continue with the rest of the troubleshooting. 3. Power cycle the modem. 4. If your ISP requires PPPoE settings, verify that you have entered them correctly. 5. If your ISP does not use PPPoE authentication, do not use these fields in the Dashboard. Shared connection with a modem and a router loadTOCNode(3, 'whattotry'); 1. Power cycle both the modem and the router. 2. Try connecting the Xbox 360 console to Xbox Live by using the modem only. This eliminates any configuration problems on the router. • If this setup works without the router, there is a configuration issue with the router. See the router's documentation or contact the technical support group. 3. Verify that your router's DHCP service has been enabled. See the router's documentation or contact the technical support group. 4. The IP address that you entered in the Network Settings area of the Xbox Dashboard may be incorrect. Set your IP settings to Automatic. 5. If your ISP requires PPPoE settings, try to connect with only the modem after you enter the PPPoE settings in Network Settings. • If you can connect, see your router documentation to configure the PPPoE settings correctly on the router. 6. If you are receiving an IP conflict error in the More Info section, turn off all the devices on the network. Try to connect with only the modem and Xbox 360 console connected. • If this works, there is a configuration issue on the routers DHCP server. See the router's documentation or contact the technical support group. Shared connection with a gateway device (combined modem and router) loadTOCNode(3, 'whattotry'); 1. Make sure that the device is turned on. 2. Verify that there is activity with the blinking lights sequence WAN, ADSL, and Internet connected power. Note These names will vary from model to model. 3. Power cycle the gateway device. 4. The IP address that you entered in to the Network Settings area of the Xbox Dashboard may be incorrect. Set your IP settings to Automatic. 5. If you are receiving an IP conflict error in the More Info section, turn off all the other devices on the network. Try to connect with only the Xbox 360 console on the network. • If this test works, there is a configuration issue on the gateway DHCP server. See the router's documentation or contact the technical support group. Shared connection with Microsoft Windows Internet Connection Sharing loadTOCNode(3, 'whattotry'); 1. Verify that you can browse the Internet. If you cannot browse the Internet, Internet Connection Sharing is not configured correctly. 2. Power cycle the modem. If the modem does not have an on and off switch, unplug the modem from the power outlet. You cannot follow this step if you are using a USB modem. Instead, go to the next step. You must follow this step if you are switching the modem between the Xbox 360 console and a computer. 3. On the computer, click Start, click Run, type ncpa.cpl, and then click OK. 4. On the View menu, click Tiles. 5. If the connection is listed as Firewalled, the firewall may have to be configured. See your firewall documentation. 6. Enter manual settings in the Dashboard for IP address, subnet mask, DNS address and gateway: • IP Address : 192.168.0.2 • Subnet mask : 255.255.255.0 • Default Gateway : 192.168.0.1 • DNS server (Primary): 192.168.0.1 • DNS server (Secondary): 192.168.0.1If none of this works you might be banned. If you modded your xbox360 or for downloading game saves from the internet to boost you gamer score. You might be banned!