[Cisco] Some Cisco router commands are constantly updated ......

Trace XXX. XXX

Show int F0/0

Show CDP neighbors

Show CDP neighbors detail

Show CDP entry *

Show CDP entry [device ID] // The device ID is obtained in sh cdp n.

Sh controllers S0/0/0: You can check which end of the S0/0/0 line is DCE.

There seems to be another method: Sh run can see the status of each port, which indicates that clock rate Xxxxx is the DCE end, but this method cannot be found before configuration.

Debug IP routing enable route table debugging

No debug IP routing or undebug IP disable route table debugging. You can also disable undebug all because we have not enabled other debugging functions.

R12001 protocol:

Router rip and then add net to each direct network. ripv1 has a class

Disable passive interface: passive-interface F0/0

Automatic summary:

Two principles to control r1_1 update:

If a route update and its receiving interface belong to the same master network, the subnet mask of the interface is applied to the network in the route update.

If a route update and its receiving interfaces belong to different primary networks, a subnet mask is assigned to the network application network in the route update.

Default-Information originate // specify the router as the default information source, and the route transmits static routes in the rip update.

VPN protocol:

Router VPN ID

Then the network number

Use the wildcard-mask option in the network command to advertise only the subnet, not the entire class network.

Generally, when the network to be declared is not a class, we need to use wildcard-mark. If there are multiple such networks, we need to manually declare them one by one. Unless we are very specific and need to summarize manually, use the following command to manually summarize:

First, enter the port that allows sending the manual summary, such as S0/0/0, int S0/0/0, and then IP Summary-address VPN as-number network-address subnet-mask, such as 192.168.0.0, 192.168.1.0 and 192.168.2.0 can be manually summarized as IP Summary-address VPN 1 192.168.0.0 255.255.252.0

Run the show ip vpn neighbors command to view the neighbor table and check whether the table is adjacent to the router R2 and R3.

Run the show IP protocols command to view information related to the running status of the routing protocol.

If Automatic summary is not disabled, a route entry to null0 is displayed in the routing table. You can disable automatic summary with no auto-summary.

First int S0/0/0, and then bandwidth 64, you can set the synchronous routing bandwidth on this port to 64, which does not affect the Internet bandwidth.

Use the interface configuration command no bandwidth to restore the bandwidth to its default value.

Run the show ip vpn topology command.

A successor router is an adjacent router currently used to forward data packets. The successor router is the lowest overhead route to the target network. The IP address of the successor router is displayed in the route table entry, followed by the word "".

Feasible distance (FD) is the minimum measurement to reach the target network. FD is the measurement listed in the route table entry, which is the second number in the brackets.

A feasible successor router is a neighbor and has a feasible standby path to the same target network connected to the successor router. To become a viable successor router, R1 must meet the feasibility requirements. When the report distance from a neighbor to a network (RD) is shorter than the feasible distance from the local router to the same target network, the feasibility condition (FC) is met ).