Matching AS_SET and AS_CONFED_SEQ
Example 13-5 shows how to use a BGP filter list to match the AS_SET and AS_CONFED_SEQ segment types. Figure 13-5 depicts the specifics of the example. In this case, R4 summarizes 16.0.0.0/4, creating an AS_SET entry for the summary, and advertising it to R1 and R3. R1 and R3 in turn advertise the route to R2; R1’s route includes an AS_CONFED_SEQ, because R1 and R2 are confederation eBGP peers. Figure 13-5 Generating AS_SET and AS_CONFED_SEQ Example 13-5 shows two ..
Determining All Subnets of a Network—Decimal
You may have noticed the trend in the third octet values in the subnets listed in the previous paragraph. When assuming SLSM, the subnet numbers in decimal do have a regular increment value, which turns out to be the value of the magic number. For example, instead of the binary math in the previous section, you could have thought the following: ■ The interesting octet is the third octet. ■ The magic number is 256 – 224 = 32. ■ 172.31.0.0 is the zero subnet, because..
802.1X Authentication Using EAP
Switches can use IEEE 802.1X to perform user authentication, rather than the types of device authentication performed by many of the other features described in this section. User authentication requires the user to supply a username and password, verified by a RADIUS server, before the switch will enable the switch port for normal user traffic. Requiring a username and password prevents the attacker from simply using someone else’s PC to attack the network without first br..
Preventing Unauthorized Configuration Modifications
You can use the snmp-server tftp-server-list configuration command to restrict which TFTP servers the router can use in response to an SNMP trigger to upload or download configuration information: Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#access-list 92 permit 172.25.1.1 Router(config)#access-list 92 deny any log Router(config)#snmp-server tftp-server-list 92 Router(c..
Displaying Historical CPU Values
To display the router's historical CPU values, use the show processes cpu history command: Router# show processes cpu history Router 03:48:18 PM Monday Apr 17 2006 EDT &n..
