Using the Local-Preference Attribute

The local preference is equally easy to configure. You can set it on either a default or a perprefix basis. The syntax for the default command is  Router(config-router)#bgp default local-preference value  Local preference has a range from 0 to 4,294,967,295; higher values are preferred in selecting routes. The default is 100.  Example 16-2 is based on Figure 16-2. The local preference, set in the San Francisco router to 200, is propagated in the updates to a..

Policy Routing for Marking

Policy routing provides the capability to route a packet based on information in the packet besides the destination IP address. The policy routing configuration uses route maps to classify packets. The route-map clauses include set commands that define the route (based on setting a next-hop IP address or outgoing interface). Policy routing can also mark the IPP field, or the entire ToS byte, using the set command in a route map. When using policy routing for marking purpose..

Setting SNMP Queue Size

The following command increases the size of a router's SNMP trap queue: Router#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Router(config)#snmp-server queue-length 25 Router(config)#end Router# To increase the size of the router's SNMP inform queue, use the following configuration command: Router#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Router(config)#snmp-server inform pending 40 Router(..

Logging Unauthorized SNMP Attempts

Use the following commands to configure your router to log unauthorized SNMP requests: Router#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Router(config)#access-list 99 permit 172.25.1.0 0.0.0.255 Router(config)#access-list 99 permit host 10.1.1.1 Router(config)#access-list 99 deny any log Router(config)#snmp-server community ORARO ro 99 Router(config)#snmp-server community ORARW rw 99 Router(config)#end Router# If you are concerned ..

Preventing Routing Domain Loops with Higher Metrics

One easy method of preventing the domain loop problem is to assign purposefully high metric values when redistributing routes. For example, consider the case shown in Figure 10-3, with a RIP domain on the left, and OSPF on the right. In this case, the two routers doing the redistribution (RD1 and RD2) assign OSPF metric 500 when redistributing routes into OSPF, and metric 5 when redistributing routes into RIP. First, focus on routes inside the RIP domain. This design preve..