DHCP

DHCP

1. DHCPv4

   • Troubleshooting DHCPv4
     • Problem solving tasks
       • DHCPv4 issues can arise due to various reasons, such as software defects in operating systems, NIC controllers or DHCP relay agents. However,
     • Verification of router DHCPv4 configuration
       • When the DHCPv4 server is located on a LAN other than the client's,
     • Debugging DHCPv4
       • On routers configured as DHCPv4 servers, the DHCPv4 process fails if the router does not receive requests from the client.
   • DHCPv4 client configuration
     • Configuring a router as a DHCPv4 client
       • On occasion, Cisco routers in small offices and home offices (SOHO) and branch sites must be configured as DHCPv4 clients in a manner similar to client computers.
     • Configuring a wireless router as a DHCPv4 client
       • Wireless routers for use in the home or a small office are connected to an ISP using a cable modem or DSL.
   • Configuring a basic DHCPv4 server
     • Configuring a basic DHCPv4 server
       • A Cisco router running the Cisco IOS software can be configured to function as a DHCPv4 server.
     • Verification of DHCPv4
       • Notice that the information about the bindings now shows that the IPv4 addresses 192.168.10.10 to 192.168.11.10 joined the MAC addresses.
     • Relay of DHCPv4
       • In a complex hierarchical network, business servers are usually located in a server farm.
   • Operation of DHCPv4
     • Introduction to DHCPv4
       • DHCPv4 assigns IPv4 addresses and other network configuration information dynamically.
     • Operation of DHCPv4
       • This lease mechanism ensures that customers who move or
     • DHCPv4 message format
       • The DHCPv4 message format is used for all DHCPv4 transactions.
     • Discover (Discovery) and Offer (Offer) messages from DHCPv4
       • If a client is configured to receive its IPv4 configuration dynamically and wishes to join the network,

2. DHCPv6

   • SLAAC y DHCPv6
     • Automatic state-independent address configuration (SLAAC)
       • Global unicast IPv6 addresses can be configured manually or dynamically.
     • Operation of SLAAC
       • A router must have IPv6 routing enabled before it can send RA messages
     • SLAAC option
       • SLAAC is the default option on Cisco routers. Both the M indicator and the O indicator are set to 0 in the RA
     • DHCPv6 option without status
       • The stateless DHCPv6 option informs the client to use the RA message information for addressing, but that there are more configuration parameters available from a DHCPv6 server.
     • DHCPv6 option with status
       • In this case, the RA message informs the client not to use the information contained in the RA message.
     • DHCPv6 operations
       • DHCPv6 without status or with status, or both, start with an ICMPv6 RA message from the router.
     • SLAAC and DHCPv6
       • The decision of whether a client is configured to obtain its IPv6 address information automatically by SLAAC,
   • DHCPv6 without status
     • Configuring a router as a DHCPv6 client without status
       • The client router needs a link-local IPv6 address in the interface to send and receive IPv6 messages, such as RS messages and DHCPv6 messages.
     • Verification of DHCPv6 without status
       • The default router information also comes from the RA message. This was the source IPv6 address of the
   • DHCPv6 server with status
     • Configuring a router as a DHCPv6 server with status
       • Setting up a DHCPv6 server with status is similar to setting up a stateless server.
     • Configuring a router as a DHCPv6 client with status
       • ipv6 enable interface configuration mode command is used to allow the router to receive a link-local address to send RS messages and participate in DHCPv6.
     • Verification of DHCPv6 with status
       • The show ipv6 dhcp pool command verifies the name of the DHCPv6
     • Configuring a router as a DHCPv6 relay agent
       • the configuration of a DHCPv6 relay agent is similar to DHCPv4, routers or IPv6 relay agents forward DHCPv6 messages slightly differently than DHCPv4 relays.
   • Resolving DHCPv6 problems
     • Problem solving tasks
       • The problem resolution process of DHCPv6 is similar to that of DHCPv4, because if there is a switch between the client and the DHCPv6 server, and the client can not obtain the DHCP configuration, the cause may be problems with the port configuration of the switch.
     • Verificación de la configuración de DHCPv6 del router
       • Router configurations for stateless and stateless DHCPv6 services have many similarities, but they also include significant differences.
     • Debugging DHCPv6
       • When the router is configured as a DHCPv6 server with status or no status, the debug ipv6 dhcp detail command is useful for verifying the reception and transmission of DHCPV6 messages.