Category: CCNA

Cisco Certified Network Associate certification resources

A clipboard with green checkmarks and red Xs next to the text "ACL Logics" on a blue background.
CCNA September 21, 2019

Inbound and Outbound ACL Logic

Access Control Lists (ACLs) are a fundamental component of Cisco networking, used to filter traffic based on predefined rules. For CCNA and CCNP students, mastering ACLs is critical for securing networks and passing certification exams. ACLs allow network engineers to permit or deny packets based on criteria like source and destination IP addresses, protocols, and […]
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Diagram illustrating Extended ACLs with permit and deny rules for IP ranges 192.168.2.0 and 192.168.2.123, showing network traffic control.
CCNA September 21, 2019

How to Configure Extended ACLs – Exclusive Explanation

The number of extended ACLs ranges from 100 to 199 and 2000 to 2699, providing 799 possible numbered ACLs. The 100-199 range was historically used, while 2000-2699 is recommended for modern networks due to greater flexibility and support for named ACLs. Choose based on your network’s complexity and Cisco IOS version. We can also create […]
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Infographic showing Cisco router VTY access control using Telnet/SSH and ACLs. Includes a centered title, configuration steps, and a network diagram with PC0 denied and PC1 permitted access to router R3.
CCNA September 11, 2019

How to Configure Standard ACLs to Secure VTY Ports

All Cisco routers and switches do not allow remote access by default via terminal programs like PuTTY or Tera Term. Remote connectivity options include Telnet (VTY Port) or SSH. SSH provides encrypted sessions and is strongly recommended by Cisco for remote administration due to Telnet’s vulnerabilities. Prerequisites for CCNA/CCNP Students However, if your router’s Cisco […]
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Infographic illustrating ACL statistics with a table showing permit and deny statements, matches, and explanations, featuring a laptop and router with permit and deny arrows
CCNA September 10, 2019

ACL Statistics in Cisco Networks: Monitoring Matches with show access-lists

Access Control Lists (ACLs) are essential for filtering traffic in Cisco networks. For CCNA students, understanding statistics helps verify if rules are working as intended. CCNP candidates should note how stats aid in troubleshooting complex setups like multi-interface ACLs. After an ACL has been configured and applied to an interface, it can block or permit […]
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Infographic showing three steps to edit standard ACLs: sequence numbers, router config commands, and named ACL examples in Cisco networking.
CCNA September 10, 2019

How to Edit Standard ACLs

Network administrators sometimes want to edit standard ACLs. As you know, each new entry you add to the Access Control List (ACL) appears at the bottom of the list, and the router assigns a sequence number to that entry automatically. Standard ACL statements are added to running-config files, but there is no built-in way to […]
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Diagram illustrating standard ACL configuration with a router blocking traffic from host 192.168.2.2 to network 192.168.4.0/24.
CCNA September 9, 2019

How to Configure standard ACLs

Standard ACLs permit or deny traffic based on source addresses. They differentiate routes on a network using the IP address. The port and destination of the packet are not evaluated. Standard ACLs only contain a list of addresses or address ranges and a statement as to whether access to or from that address is permitted […]
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Diagram of TCP three-way handshake process showing SYN, SYN-ACK, and ACK exchanges between two hosts for connection establishment.
CCNA September 2, 2019

Understanding TCP Three-Way Handshake: A Comprehensive Guide (Updated 2025)

In networking, the TCP three-way handshake (often called a “TCP conversation”) establishes reliable connections, which is crucial for Access Control Lists (ACLs) to filter traffic effectively. ACLs manage inbound and outbound traffic based on IP addresses, ports, and TCP flags. This article explains TCP fundamentals before diving into ACL integration, helping CCNA students grasp transport […]
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Diagram and configuration commands for setting up OSPFv3 on a network.
CCNA September 1, 2019

How to Configure OSPFv3: Complete Guide (Updated 2025)

Figure 1 shows the reference topology for configuring OSPFv3. You can also see the commands for configuring OSPFv3 for IPv6 unicast and link-local addresses on the interfaces of Router1. As identified in the referenced topology, assume that Router2, Router3, and Router4 interfaces have already been configured with the global IPv6 and link-local addresses. This topology […]
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Illustration of interconnected routers demonstrating link-local IPv6 address concept
CCNA September 1, 2019

What is a Link-Local IPv6 Address – Exclusive Introduction

Routers configured with dynamic routing protocols such as OSPF or EIGRP must send and receive routing protocol messages with their directly connected neighbors. The routers exchange messages between neighbors on the same subnet. These messages are always sent from the router’s source IPv4 address. Link-local IPv6 addresses are perfect for this purpose. The address also […]
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nfographic comparing similarities and differences between OSPFv2 and OSPFv3 routing protocols, including link-state features, metrics, areas, packet types, router ID, advertised routes, multicast addresses, authentication, and LSA types.
CCNA September 1, 2019

OSPFv2 vs OSPFv3: Key Differences and Similarities

OSPFv3 is a routing protocol for IPv6, just as OSPFv2 is for IPv4. While both share core principles, there are vital differences in their operation. OSPFv3 serves as the IPv6 equivalent to OSPFv2 for exchanging prefixes, making it essential for modern networks handling dual-stack environments. In IPv6, the network address is referred to as the […]
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