cisco ccna certificate

cisco ccna certificate.In DHCPv4, the IP Helper feature needs to be configured on the Cisco routing device when the client and DHCP server are not in the same network segment. IP Helper lets the router redirect DHCP requests to a specific server or to a directed broadcast address on the segment containing the DHCP server.In DHCPv6, this feature is not required: if there are no servers on the current link, the relay agent can forward the request to a multicast address that represents all DHCP agents and has a range of site locality. You can also do this statically: it is required when you need to control which DHCPv6 servers the request should be processed by.23.4.3 Stateless Auto-ConfigurationStateless autoconfiguration is an extension to DHCPv6. Like DHCPv6, stateless autoconfiguration allows clients to dynamically obtain addressing information, but does not require the use of a DHCP server to assign this information to the client. Instead, the client configures the interface with an IPv6 address based on the information in the router announcement message: the first 64 bits (the prefix of the router address) are obtained from the source address advertised by the router, and the EUL64 method is used to generate a 64-bit interface IDO The main purpose of stateless autoconfiguration is to allow mobile phones, home networks, and appliances to be automatically assigned addresses while eliminating the need to manage the DHCP server infrastructure. Before using an automatically assigned address, the device will use ICMPv6 to send a neighbor lookup message to verify that the address is unique.Exam Essentials Stateless Auto Configuration does not require a DHCP server to automatically assign addresses. The device learns the IPv6 prefix from the router announcements and automatically generates the interface ID portion of the address using EUI-64.Typically, routers generate router announcements (RAs) periodically, and clients can listen for and use RAs to automatically generate their link addresses. However, when a client starts up, it may have to wait a while to receive an RA; in this case, the client will generate a router request message, asking the router to answer using the RA, allowing the client to generate its interface address.The information available through stateless autoconfiguration includes: . The network number (prefix); . The life cycle of the prefix .. A flag indicating which autoconfiguration (stateless or stateful) the client can perform; . The default route for the prefix and the lifecycle of that route; .. The default MTU of the network segment; . The maximum number of hops allowed. The most common parameters are listed above, but additional information is available.Authentication Target 23.05