Antivirus measures are still required to use the router

If you are connected to the Internet via a router, is it safe to not install anti-virus software? Should you install antivirus software?

Even if you use a router to access the Internet, you must also install anti-virus software. The router has the function of address translation and opening and closing TCP/IP communication ports. While these features prevent some attacks from the internet, such as virus propagation, there are still attacks that can not be stopped.

Routers cannot completely prevent attacks

For example, routers cannot defend against viruses in message attachments. Because the virus has been saved as part of the email to a personal computer. In addition, viruses that are contained in software downloaded from the Web cannot be detected.

So what kind of attack can routers prevent? TCP/IP communication on the Internet uses the global IP address to Exchange data with terminals such as the personal computer of the contact party. The global IP address is the IP address assigned by the service provider when the user is connected to the Internet. Routers have the ability to share this common IP address on multiple pcs (called IP camouflage, IP masquerade).

If you use the address translation function, you can use a fixed IP (Private IP) address on each PC that has a shared access line. A fixed IP address is an IP address that can be used freely in a LAN that is not directly connected to the Internet, and is automatically allocated by routers.

Security features for routers

Almost all routers have packet filtering capabilities that can be controlled based on different port numbers.

Fixed IP is not available on the Internet (cannot be routed), it is very difficult to access a personal computer with this address directly via the Internet. That is, the possibility of an external intrusion on a PC that has access to the Internet via routers is slim.

In addition, the port number is also used in TCP/IP communications. Data is transmitted to the target PC via an IP address, but the port number is required to distinguish which application in the target PC is using the data. The port number used by the general application software is fixed, and the router determines the pass or intercept of the data according to the port number (shutdown port, etc.).

Viruses such as the recently raging w32/msblaster exploit vulnerabilities in software (services) that use specific port numbers, so that only proper use of the router's port shutdown feature can effectively prevent this type of virus infection.