Network security of small businesses is pivotal with evolving technology. Presently most small business users tend to use the Internet as their main source of marketing, storing sensitive information, and performing business processes. Compared to large companies, small business networks often neglect information security. Most of the existing solutions that integrate advanced technologies like machine learning are not cost-effective for the target audience. To address the security concerns, this research proposes an innovative approach named ‘NetNexus’ an intelligent network monitoring device built on a Raspberry Pi module. The proposed model provides an Access control list that is integrated with a malware detector with 85% accuracy, a brute force attack detection, and a user-behavior-based quota allocation model with 91% accuracy. Furthermore, the NetNexus device is integrated with a device security mechanism with a Physically Unclonable function to protect the device from tampering and cloning. NetNexus is targeted at small businesses that neglect the need for network security due to the high expenses in implementation. This product has focused on a cost-effective approach which will cost around 1500 USD, and alternatively, it is efficient as only one single device is capable of securing the network and managing the performance.