Windows 2003 system uses SyGate agent to access the Internet fault

The school computer room recently upgraded the system to Windows 2003. In order to strengthen management, we gave up the ICS share that comes with Windows and shared the Internet using SyGate agent. Unexpectedly, a series of problems occurred during the use, the author spent a lot of brains.

Fault 1: After SyGate is enabled, all student computers in the school can share the Internet. The server has the ability to access the Internet when it is turned on, and it cannot access the Internet after a few minutes.
Fig. 1 Prompt box for playing y out after configuring multiple gateways

Analysis of the reason: Since the student machine can access the Internet, the network is connected. We switched to Windows' own connection sharing and everything works fine, so it is inferred that the cause of the failure is probably a SyGate configuration problem. However, no matter how you change the settings, the fault still exists.

At this time, the author suddenly thought of one thing: when configuring the IP address of two network cards and other information, we have set their respective gateways to different values, and when the settings are completed, The dialog shown in 1. SyGate is a gateway-like proxy software. Is there a problem with SyGate caused by two gateways configured in the NIC properties? So we reset the gateway of the internal network NIC in the network settings and restart the computer, the failure disappears.

Fault 2: After the above faults are resolved, the server is running stably. We make full use of the management functions of SyGate to manage the engine room. One day, however, it was suddenly found that the server and some computers could ping each other but could not be accessed through the network neighborhood (Figure 2).
Figure 2 Fault Diagram

Cause Analysis: Since the computer that cannot be networked with the server belongs to the network segment 10.1.13, we suspect that the network card with IP address 10.1.13.3 has a problem. So, we uninstalled this NIC and replaced a new NIC and reset it. The fault persists. Since there is no hardware problem between them, the detection focus will be on the configuration of the network card and the configuration of the network management software.

Through careful analysis, we finally found the reason: a colleague checked the "Enable Enhanced Security Mechanism" in the configuration dialog box if you are not familiar with the software (Figure 3). Make SyGate act like a firewall in disguise. After removing the "Enable Enhanced Security" option, everything is back to normal.

Figure 3 SyGate configuration dialog