How do you enable TCP reassembly in Wireshark?

• A. Preferences → Protocols → TCP, enable “TCP reassembly,” and enable related options such as “Reassemble out of order segments” and “Reassemble TCP streams.”
• B. Right-click a TCP packet and choose 'Reassemble'
• C. Edit → Preferences → TCP
• D. TCP reassembly is automatic; no settings exist.

Answer: (A)

TCP reassembly reconstructs the original byte stream from multiple TCP segments so Wireshark can display a continuous flow of data rather than treating each segment in isolation. This is important because TCP data can arrive out of order or be captured in fragments, and reassembly makes higher-layer protocols (like HTTP or TLS) much easier to interpret.

To enable it, open Wireshark preferences, go to Protocols, select TCP, and enable TCP reassembly. Also enable related options such as Reassemble out of order segments and Reassemble TCP streams. These settings reorder segments that arrived out of order and reconstruct complete application data streams across multiple packets for accurate analysis. Per-packet right-clicks don’t toggle this feature; it’s a global setting under TCP preferences.