Everyday Ten Ask ccie r&s lab version

1. Question: What is the meaning of the show spanning-tree of the false and true under summary?

Answer: False is a non-edge port and true is an edge port. The method of judgment is that if the switch receives bpdu, it will become false. Did not receive bpdu, the port will be over the detection time After the automatic conversion to the edge port, the timeout period is about 3-5s (different items may differ)

2. Problem: The indicator of the switch interface connected to the AP is normal but the indicator connected to the computer is not lit and the data can be forwarded normally.

Answer: POE device with POE button. If the POE button is pressed, all interfaces connected to the non-POE power supply will be off, including the optical port but the interface connecting the POE device will be on and the normal data forwarding lamp will be displayed without pressing the POE button.

3. Problem: When the firewall is drained, configure the bridge. Before the drain, it is vlan 10. After the traffic is vlan 1001. Configure the ip address on the vlan 1001 to ping the terminal that does not pass the same network segment.

Answer: Interface vlan 10 that also the SVI interface before the drainage to be deleted, only the SVI after the drainage is the gateway.

4. Question: When the ip source guard+arp-check scheme is configured, which entry is arp-check called?

Answer: Arp-check calls ip source. The guard entry is not a dhcp snooping entry.

5. Question: How does the N18K view the voltage?

Answer: You can check the voltage condition by the following command: show card voltage.

6. Problem: After the PC connects to the normal Layer 2 switch to obtain the address and then connects to the switch. Even if the switch has DHCP enabled. SNOOPING, after the PC network card is reconnected, the address of dhcp will still be obtained.

Answer: The DHCP address obtained before the PC was not released which caused this to happen. Use the ipconfig/release command to release the address.

7. Question: After the switch, where the HCP address pool is located is restarted. A large number of DHCP address conflict logs will appear.

Answer: In order to prevent this from happening, you need to configure a command before restarting, write the DHCP database before the restart to flash and still follow the database after restarting. Address that information still exists, the command is: Switch (config) # ip dhcp database write-to-flash can also be automatically written, but the time can not be too short, Switch (config) # ip dhcp database write-delay + interval (seconds)

8. Question: What is the situation with NAK messages in DHCP?

Answer: NAK: Negative Response Message. When the terminal sends a request message to the server, the server verifies whether the ip address resource is assignable. If not, sends a NAK message. The terminal must re-initiate the discovery message.

9. Question: How do dual exits detect routes?

Answer: Switch save in the case of dual-exit, the BFD detection is used in the configuration and the floating static route is used to implement the routing export problem (the floating static route is modified by the AD value).

10. Question: Is the login local locale not configured with a username and password?

Answer: The device will not be able to log in, especially if line console 0 is configured. Only password reply can be made at this time.

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