Alternatives to the OSPF Network Command
As of Cisco IOS Software Release 12.3(11)T, OSPF configuration can completely omit the network command, instead relying on the ip ospf process-id area area-id interface subcommand. This new command enables OSPF on the interface and selects the area. For instance, on R3 in Example 10-8, the network 10.3.0.0 0.0.255.255 area 3 command could have been deleted and replaced with the ip ospf 1 area 3 command under S0/0.1 and e0/0. The network and ip ospf area commands have some mi..
Calculating Classfully Assumed Network Ranges
A common task in addressing is to take an IP address and to understand the range of addresses that are on the same network. Originally, this was done by reading the first bits of the address to determine a class; this is called classful addressing. The portion of the address consumed by the network prefix was then assumed, based on that class. Table 2-2 shows the first bits of an IP address, the corresponding classes, and the number of bytes assumed to be in the network..
IS-IS is a link-state routing protocol. IS-IS does not advertise routes like the distance vector protocols. IS-IS advertises link states using link-state packets (LSPs). IS-IS routers flood, or advertise, their link states to their IS-IS neighbors throughout an IS-IS area. If a router is configured only as a Level 1 IS-IS router, that router will maintain one IS-IS database for that area. If a router has been configured as a Level 1-2 router, the router maintains a separate d..
Cisco security and IDS provide a mechanism to detect when an intrusion has occurred. The only problem in an HIDS is that a lot of alarms are false positives, especially in a large installation base of CSA clients. In other words, many alarms need not cause your security team to investigate a normal IP packet or TCP segment, for example. A CCIE candidate, however, must be able to tune out normal IP packets and TCP segments in the CCIE lab portion of this certification. The mai..
The NBAR feature is used to identify traffic within a class-map. You can then use the class-map in a policy-map to define how the router should handle each application data stream: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#ip cef Router1(config)#class-map INTERACTIVE Router1(config-cmap)#match protocol citrix Router1(config-cmap)#match protocol telnet Router1(config-cmap)#exit Router1(config)#policy-map QoSP..
