cisco 200-301 exam format

cisco 200-301 exam format.You first need to specify the IP address of the remote NTP server. If you do not specify an NTP version number, the default is 3 (NTPv3). The optional parameter key specifies the authentication information used to authenticate the time message to the server or peer: it must be the same information used by the server to perform NTPv3 authentication (the usage of this parameter will be described later). o The parameter source specifies that when sending data to the remote NTPserver when sending data, which IP address of the IOS device is used as the source address in the IP packet header (note that the IP address to be used is specified by specifying the Layer 3 interface of the IOS device); if this parameter is omitted, the default is the address of the Layer 3 outbound interface. When multiple NTP servers are configured, use the parameter prefer, which specifies that this NTP server is used first to synchronize the time; if this parameter is not used, the IOS device first queries the first server configured.To configure authentication, three commands are used.ntp authenticate ntp authentication-key key_# md5 key_value ntp trusted-key key_#IOS(config)# command ntp authenticate Enables NTP authentication. The command ntp authentication-key defines the key number (key_#) and authentication key (on remote NTP servers, the same key_# and key_value must be configuredo Finally, the command ntp trusted-key specifies which NTP devices are trusted to avoid inadvertently synchronizing with untrusted systems. Note that a key number is specified in this command, and it must be the same as the key number defined by the command ntp authentication-key. By using the key number, multiple keys can be created, allowing you to more easily modify keys and use different keys for different peers.After configuring authentication, you need to specify the key number in the command ntp server to let the IOS device know which key to use when sending messages to a specific peer.17.1.3 Authenticating NTPAfter NTP is configured on an IOS device, various show commands can be used to view and troubleshoot the configuration. To view the current time of the router, use the command show clock (which was discussed in Chapter 10) oThere are two basic commands for viewing NTP information.. show ntp associationso