In TCP/IP networking, the ACK flag is used to acknowledge the receipt of a packet. It's a way to confirm that the previous packets have been received and that the connection is proceeding as expected. The RST flag, on the other hand, is used to reset the connection. It is sent if a segment arrives which is not intended for the current connection, or if a connection request is to be denied. Essentially, the ACK flag is about maintaining the established connection, while the RST flag is about aborting connections that are not valid or are no longer needed123.
The information provided is based on standard TCP/IP protocol behavior as described in networking resources and Cisco's cybersecurity documentation

Enabling the "Allow subdissector to reassemble TCP streams" feature in Wireshark allows the tool to reassemble TCP segments into a contiguous sequence, which can be used by higher-level protocols to reconstruct a full message, such as an HTTP request or response. This is particularly useful for extracting files or data transmitted over TCP that are spread across multiple packets1.
References := The explanation is based on the Wireshark documentation, which details how the reassembly feature works and its use in analyzing TCP streams

Indicators of Compromise (IoC) are pieces of forensic data, such as system log entries or files, that suggest an intrusion may have occurred. Indicators of Attack (IoA) are signs that an attack may be underway, allowing organizations to take action before any potential breach occurs.
The CBROPS course materials cover the concepts of IoC and IoA, explaining how they are used in cybersecurity operations to detect and prevent security incidents.