NAC network access control makes it difficult to implement network security.

NAC Network Access Control) is a huge topic widely discussed in the industry and also the focus of many vendors. Over time, this acronym has almost become a popular term that is overused, and there are also many variants in definition. When I asked some itmanagers how they defined NAC, they agreed that NAC involves three factors:
· Access Control, which selectively allows a host to join into the network and maintain its connection capabilities-is also one of the key to NAC. This is what everyone who answers my questions agrees.
· Security check. This is the capability to check whether patch, anti-virus, and other functions of the integrated system have been upgraded in a timely manner. This is an important part of the NAC defined by most respondents.
· Access Control: This is the ability to control what the connected host can see or do. Among the people I have asked, only a few people think that this capability is ideal for the NAC system. CISO information Auditors working at a financial company explained that this capability is "a capability to first confirm its legitimacy before the endpoint system is connected to the network, then control where the system can go, which is similar to the customer management system."
A few of the respondents are now practicing NAC. Only 14% of people said they would check for application and OS patch upgrades for endpoints; check for existence of firewall, anti-virus and anti-spyware; check for USB interface devices; and the degree of confidentiality of passwords. However, nearly 60% of people say they want to check at least firewall, anti-virus, anti-spyware and other tools; about 40% require password and OS checks. Less than 1/3 of users want to perform application checks.
The cost and complexity can explain why there is a big difference between the desired check level and the actually achievable check level. Implementing NAC requires additional network infrastructure and sometimes even updating existing network devices. For example, to perform network access authentication on the switch port, you need to be able to support 802.1x Standard devices. Although few people are investing money in implementing NAC, everyone feels that the company's investment in NAC will definitely increase in the future.
Implementing access, security, and access control over endpoints sounds really attractive. However, so far, no enterprise has fully overhauled its network. As more widely accepted interoperability protocols are required, therefore, the use of NAC is likely to be slow and sporadic.