Network forensics plays a vital role in modern cybersecurity by enabling the investigation, detection, and tracking of malicious activities within a network environment. We provide an overview of network forensic techniques, tools, and challenges and discuss analyzing network traffic to gather evidence of cyberattacks. It consists of two types of analysis which are real-time and post-incident. The importance of ensuring data accuracy, identifying sources, and protecting privacy during investigations are emphasized. We also explore email forensics, which involves examining email content and headers to trace the origin of messages and identify attackers. The elements such as header analysis, message tracing, and protocols (e.g., SMTP, HTTP) are also discussed in this paper. Moreover, we explain how network and email forensic tools support incident response and also explore the challenges, such as dealing with fake data and protecting digital evidence.