## Introduction In computer networking, IP address subnets are used to divide larger networks into smaller, more manageable segments. A **/30 subnet** refers to a subnet mask of 255.255.255.252, which allows for four IP addresses per subnet (two usable host addresses, one network address, and one broadcast address). Calculating the network addresses of consecutive /30 subnets can become repetitive if done manually each time, especially when organizing or planning IP address allocation for routers, point-to-point links, or other network devices. Therefore, knowing a shortcut for determining the network addresses for consecutive /30 subnets can save time, reduce human error, and make network management more efficient. This solution will provide a step-by-step explanation of the shortcut method to quickly find network addresses of consecutive /30 subnets. --- ## Step-by-Step Solution ### Step 1: Understand the /30 Subnet - An IPv4 /30 subnet mask is 255.255.255.252. - Each /30 subnet contains **4 IP addresses** (2 usable, 1 network, 1 broadcast). - The block size for a /30 subnet is **4**. ### Step 2: Identify the Shortcut - The network address of each consecutive /30 subnet increases by **4**. - Shortcut: **Add 4 to the last network address to get the next subnet's network address.** ### Step 3: Apply the Shortcut Let’s start with an example starting address: **192.168.1./30** **First subnet:** 192.168.1./30 **Second subnet:** 192.168.1.4/30 **Third subnet:** 192.168.1.8/30 **Fourth subnet:** 192.168.1.12/30 ...and so on. Each time, simply add **4** to the last octet of the previous network address. ### Step 4: Generalize the Rule - For any starting IP address X.Y.Z.A, the next /30 subnet is at X.Y.Z.(A+4). ### Step 5: Final Answer **Shortcut:** To calculate the network addresses of consecutive /30 subnets, **add 4 to the last octet of the previous network address for each new subnet. --- ## Explanation Recap - /30 subnets increment by 4 in the last octet. - This shortcut avoids manual binary or mask calculations. - Simply keep adding 4 to the network address to get the next /30 subnet address. --- **Final Answer:** **The shortcut is to add 4 to the last octet of the current network address to find the network address of the next consecutive /30 subnet.**