A firewall is a device or software that filters and controls the incoming and outgoing network traffic based on predefined rules. A firewall can block ICMP packets, which are used for ping and other diagnostic tools. If the workstation has a firewall enabled, it may not respond to the ICMP sweep and appear as offline. The engineer should check the firewall settings on the workstation and allow ICMP traffic if needed.

Explanation
Port 53 is used for DNS, which is a service that translates domain names into IP addresses. Port 995 is used for POP3S, which is a protocol for receiving email messages securely. POP3S supports large file transfers and encryption. Therefore, these two ports should be opened for the mail server and the DNS server project

Integrity is the security concept that is related to ensuring that encrypted data is not edited while in transit. Integrity is one of the three main goals of information security, along with confidentiality and availability. Integrity means that data is protected from unauthorized modification or corruption during storage, processing, or transmission. Integrity can be achieved by using various techniques, such as hashing, digital signatures, checksums, or message authentication codes (MACs). These techniques can verify the authenticity and validity of the data by detecting any changes or tampering that may have occurred. Reference: [CompTIA Network+ Certification Exam Objectives], What Is Data Integrity? | Definition & Examples | Forcepoint

The disadvantages of RIP (Routing Information Protocol) include the following.
---Outdated, insecure, and slow. This is your parents' protocol. It was a thing before the Web was born.
---The more well-known problem of the 15 hop limitation in which data must travel
---Convergence time is terrible for information propagation in a network
---Metrics. It determines the number of hops from source to destination, and gives no regard to other factors when determining the best path for data to travel
---Overhead. A good example would be routing tables. These are broadcast at half-minute intervals to other routers regardless of whether the data has changed or not. It's essentially like those old cartoons where the town guard in the walled city cries out, '10 o' the clock and all is well!'.
RIPv2 introduced more security and reduced broadcast traffic, which is relevant for some available answers here.

Crimping the cable as a straight-through cable is the most likely fix for the issue where users are unable to access any network resources after upgrading from Cat 5 to Cat 6 cables. Crimping is a process of attaching connectors to the ends of cables using a tool called a crimper. A straight-through cable is a type of twisted-pair cable that has the same wiring scheme on both ends, meaning that each pin on one end is connected to the same pin on the other end. A straight-through cable is used to connect devices that operate on different layers of the OSI model, such as a computer and a switch, or a switch and a router. If the newly installed cable is crimped with TIA/EIA 568A on one end and TIA/EIA 568B on the other end, it becomes a crossover cable. A crossover cable is a type of twisted-pair cable that has opposite wiring schemes on both ends, meaning that each pin on one end is connected to a different pin on the other end. A crossover cable is used to connect devices that operate on the same layer of the OSI model, such as two computers or two switches. Using a crossover cable instead of a straight-through cable can cause network communication errors or failures. References: [CompTIA Network+ Certification Exam Objectives], Straight Through vs Crossover Cable: What's The Difference?