Year: 2019

DHCPv6 operation 6-step flowchart: Router Solicitation → Advertisement → SOLICIT to servers → Unicast Advertisement → REQUEST/INFO-REQUEST → Reply
CCNA October 5, 2019

DHCPv6 Operation: Avoid Costly IPv6 Configuration Mistakes

Both of the stateless and stateful DHCPv6 operations are started with an ICMPv6 RA message from the router. The RA message may have been periodic or solicited by the device using an RS message. The devices start client and server communication when stateless or stateful DHCPv6 is indicated in the RA message. The DHCPv6 operation […]
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Diagram illustrating three IPv6 address assignment methods via Router Advertisement (RA) flags: SLAAC (M=0, O=0), Stateless DHCPv6 (M=0, O=1), and Stateful DHCPv6 (M=1, O=1). Each section shows how a client interacts with a router and optionally a DHCPv6 server to obtain IPv6 configuration.
CCNA October 4, 2019

SLAAC and DHCPv6 – Exclusive Details

Remember that we already discussed the introduction of the SLAAC and DHCPv6 in Router Advertisement (RA) messages. Now, we will briefly discuss both SLAAC and DHCPv6. Recall that the router sends a Router Advertisement (RA) message. The setting of the Router Advertisement (RA) message decides whether a client can obtain its IPv6 address information automatically […]
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Network topology diagram in Cisco Packet Tracer showing routers, switches, servers, and laptops. Laptop0 displays a DHCP failure message with APIPA fallback.
CCNA September 30, 2019

What is DHCPv4 Relay?

In enterprise networks, dedicated servers are usually used to provide DHCP, DNS, TFTP, and FTP services. The clients are not generally on the same subnet as those servers. The clients used to broadcast messages to locate the servers and get services. Now, look at the figure below. Laptop0 is attempting to acquire an IPv4 address […]
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Diagram illustrating DHCPv4 server configuration and verification with a Cisco router and DHCP client.
CCNA September 29, 2019

Master DHCPv4 Server Configuration (Updated 2025)

A Cisco router can be configured as a DHCPv4 server. The DHCPv4 server assigns and manages IPv4 addresses from specified address pools within the router to DHCPv4 clients. The steps for configuring the DHCPv4 server on Cisco routers are the following: Excluding IPv4 Addresses The router configured as the DHCPv4 server assigns all IPv4 addresses […]
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DHCPv4 message format table showing fields like OP Code, CIADDR, YIADDR, and DHCP options with bit lengths.
CCNA September 28, 2019

Understanding DHCPv4 Message Format

Dynamic Host Configuration Protocol version 4 (DHCPv4) is a cornerstone of IP address management in IPv4 networks, automating the assignment of IP addresses, subnet masks, default gateways, and other network parameters. Based on the Bootstrap Protocol (BOOTP), DHCPv4 uses UDP ports 67 (server) and 68 (client) to exchange messages between clients and servers. This article […]
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Diagram illustrating the DHCPv4 process with a server offering an IP address to a client.
CCNA September 26, 2019

Understanding DHCPv4: A Comprehensive Guide

In modern networking, every device requires a unique IP address to communicate effectively. Understanding IP address management is crucial for network management. Static IP addresses are manually assigned to devices like routers, servers, and printers with fixed locations, enabling easy remote management. However, managing IP addresses for mobile or frequently changing devices is challenging, which […]
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Diagram illustrating the three-step process of configuring IPv6 ACLs, including creating a named ACL, using permit or deny statements, and applying to an interface.
CCNA September 22, 2019

Understanding IPv6 ACLs Configuration: Step-by-Step Guide

Access Control Lists (ACLs) are a fundamental component of network security, and understanding IPv6 ACLs is essential for CCNA and CCNP certification candidates. As networks transition from IPv4 to IPv6 to accommodate the growing number of devices, mastering IPv6 ACL configuration is critical for securing modern networks. This comprehensive guide explains IPv6 ACLs, compares them […]
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