September 16, 2025 - Reading time: 3 minutes

When you’re given a narrative like the BrightSide Graphics scenario, the goal isn’t to immediately start typing commands. Instead, you work backward from the constraints and requirements in the story to figure out the right tools and configuration.

In real life, you’ll often have to read between the lines — the boss or a client rarely says “configure PAT with overload on the interface and an inbound ACL.” They give you symptoms, policies, and limitations. Your job is to translate those into the exact features and commands that meet all needs without breaking anything else.

For this scenario, your reasoning process goes something like this:

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September 9, 2025 - Reading time: 4 minutes

In the previous lessons, we focused on Static NAT for inbound connections, including restricting traffic to specific services. For this lesson, we move to outbound internet access for inside users, using Port Address Translation (PAT), also known as NAT Overload.

PAT is a form of Dynamic NAT that allows multiple internal devices to share a single public IP address. It achieves this by assigning a unique port number to each connection. When a user inside the network wants to access the internet, the router changes the source IP address of the packet from the private internal address to the public external address and assigns a unique port number. This clever mechanism allows hundreds or even thousands of devices to share one public IP address, making it the most common form of NAT used in home and business networks.
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August 26, 2025 - Reading time: 3 minutes

The CCNA 200-301 exam gives you 120 minutes for roughly 100–120 questions, which averages to about one minute per question. In practice, though, not all questions take the same amount of time. Multiple-choice theory questions can be answered in 20–40 seconds if you know the material cold, while labs and simulations may take several minutes. That means you need to “bank” time on quicker questions—including subnetting—so you’re not rushed later on. Think of subnetting speed as a form of time insurance: the faster you get at it, the more breathing room you’ll have for complex scenarios.

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August 12, 2025 - Reading time: 3 minutes

In the previous lesson, we learned how to configure basic Static NAT to permanently map an internal address to a public IP so that external users can access it. That configuration allowed all ports to pass through to the inside host.

In this lesson, we take that concept further by applying port-specific static NAT so that only a single service — in this case, HTTP on TCP port 80 — is reachable from the internet. This provides more control over what is exposed while still giving outside users access to the intended service.

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July 29, 2025 - Reading time: 3 minutes

Previously, we set up a simple two-router lab using both iBGP and eBGP, and we also demonstrated how to verify them. Now, we'll explore how eBGP and iBGP work together to exchange routes between different Autonomous Systems (ASes), highlighting their combined role in interconnecting more complex networks.

Topology Overview

This three-router topology connects three ASes:

       (AS 5110)       (AS 2640)        (AS 2640)
      Router0  -------- Router1 -------- Router2
   (192.168.158.49)  (192.168.158.51)  (192.168.74.14)

• Router0 (AS 5110) connects to Router1 (AS 2640) using eBGP.
• Router1 (AS 2640) connects to Router2 (AS 2640) using iBGP.
• Only two static routes are used for initial reachability.

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July 16, 2025 - Reading time: 2 minutes

Static NAT (Network Address Translation) is used to create a consistent one-to-one mapping between a private internal IP address and a public external IP address. This allows internal devices, such as web or mail servers, to be accessible from external networks using a fixed public IP address.

In this lesson, we will focus on IP-only static NAT, where only the address is translated — ports remain unchanged. This form of NAT is typically used when an internal device must always be reachable from the outside using the same public IP address.

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