China Telecom's anti-Routing Method for Internet access (1)

There are two ways for ADSL to share Internet access: proxy and address translation NAT, in fact, the principle of routing and NAT is still different. We will not discuss it here. Currently, ADSL cats generally have NAT functions. It is more economical and convenient to use its own functions to achieve Internet sharing, this article mainly discusses this method.

If you want to block more than one computer from accessing the internet, you must find that there are more than one machine behind the sharing, as shown in NAT working principle 1, after NAT translation, the addresses of computers accessing the Internet over the Intranet are all changed to 192.168.0.1, And the MAC address is also converted to the MAC address of ADSL. That is to say, in principle, you cannot find several machines accessing the internet by directly capturing NAT-converted packets at the ADSL egress. How did we find it? After research, it is found that it uses a variety of methods to detect whether users use the Internet sharing mode, thus limiting, the following are cracked:

1. check whether there are different MAC addresses in the packets with the same IP address. If so, determine that the user shares the internet. The solution is to change the MAC address of each server to the same one. The modification method is as follows:

First, obtain the MAC address of the Local Machine: the MAC address is the physical address that is fixed in the serial EEPROM on the NIC, usually with 48-bit length. The ethernet switch implements packet switching and Transmission Based on the MAC source address and MAC destination address in a packet header.

(1) In Windows 98/Me, choose Start> RUN> enter winipcfg> enter.

(2) in Windows 2000/XP, click Start → run → Enter CMD → press ENTER → enter ipconfig/all → press Enter.

Alternatively, right-click the local connection icon, select the status, and click the support tab. "details" contains MAC and other important network parameters.

1. If your NIC Driver directly provides the clone MAC address function, such as the RTL8139 chip from RealTek, congratulations. Click Start → set → control panel ", double-click "network and dial-up connections", right-click the NIC icon to modify the MAC address, and select "properties ". On the "General" tab, click the "configuration" button and click the "advanced" tab. In the "attribute" area, you should see a project called "Network Address" or "Locally Administered Address", click it, and under the "value" on the right, enter the MAC address value you want to specify. You must enter 12 numbers or letters consecutively. Do not enter "-". After the system is restarted, the settings take effect. The Windows 98 and Windows 2000/XP user operations are slightly different. Please refer to the System Instructions)

2. If your NIC driver does not provide the clone MAC address function, here are some methods to find a suitable one for you.

WIN98:

A. right-click the "Network Neighbor" icon and select "properties". A "network" dialog box is displayed. In the "configuration" box, double-click the NIC you want to modify and a NIC attribute dialog box is displayed. In the "advanced" option, click "Network Address" under the "attribute" identifier, and select the preceding one from the two single options on the right, enter the MAC address of the network adapter you want to modify in the box, and click "OK", the system will prompt you to restart. After restarting, your NIC address will be modified !!

B. Click "Start> Run", type "winipcfg", select the NIC you want to modify, and record the MAC address value. Click "Start> Run" and enter "regedit" to run the Registry Editor. before modifying the registry, you must back up the Registry.) based on the registry tree structure, find "HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ Services \ Class \ Net" in sequence, and you will see subkeys like "0000", "0001", and "0002. Click the "0000" sub-key and search for the content of the "DriverDesc" key under the sub-key until you find the NIC registry information that is exactly the same as the target.

After finding the correct Nic, click "Edit> New> string" in the drop-down menu, and the name of the string is "networkaddress". Double-click the name of the newly created "networkaddress" string, you can enter a value. Enter the new MAC address value you specified. The new MAC address should be a 12-digit number or letter with no "-", similar to "00C095ECB761.

There are two ways to activate a new MAC address:

If you are using a common built-in Nic, you must restart the computer to make the change take effect.

If you are using a PCMCIA card, follow these steps without restarting the operating system: Run winipcfg, select and release DHCP settings, and disable winipcfg. Open the control panel or System Tray "PC Car (PCMCIA)", stop and bring up the PCMCIA Nic. Re-insert the PCMCIA Nic, open winipcfg, select and refresh DHCP settings, run winipcfg, and confirm that the modified MAC address has taken effect.