packetsniffing

Packet sniffing, or packet capture, is the practice of intercepting and logging network packets as they traverse a network. The goal is to analyze traffic, diagnose problems, study network performance, troubleshoot applications, or monitor security and behavior. Sniffing can occur on wired networks by placing a network interface card into promiscuous mode, using a network tap, or relying on switch SPAN/mirror ports that duplicate traffic to a monitoring station. On wireless networks, monitoring mode enables capture of frames in the air; encrypted traffic may be unreadable without keys.

Sniffers, the software that performs capture, include tools such as Wireshark, tcpdump, Tshark, and related protocol analyzers. A capture typically records packet headers (such as Ethernet, IP, TCP/UDP) and can include payload data depending on permissions, hardware, and encryption. Captured data is used for troubleshooting, protocol analysis, debugging, performance measurements, intrusion detection, and forensic investigations.

Ethical and legal considerations are central. Intercepting traffic without authorization is illegal in many jurisdictions and violates privacy. Organizations should implement policies, access controls, and auditing to limit who can capture traffic. In wireless environments, encrypted traffic remains protected from casual inspection; decrypting requires keys and may still be constrained by privacy laws and contractual agreements.

Sniffing introduces security risks: captured data can reveal credentials, confidential information, and personally identifiable information. Defenses include encrypting traffic with TLS or VPNs, network segmentation, strong access controls, and monitoring for unauthorized sniffing. Limitations include encrypted payloads, hardware limits, high data volumes, and the need for appropriate placement of sensors.