Everyday Ten Ask CCIE RS

1. Question: The log prompts the interface to receive the spanning tree timer timeout information?

Answer: Close the interface BPDU, the log will not prompt.

2. Question: How do I download files in shell mode?

Answer: run-system-shell

Cd /var/tmp/coredump

Tftp -I core-xxx-p x.x.x.x

(coredump file name, press the tab key after entering the core will be filled) (pc ip, Pc needs to open the tftp client program)

Exit

3. Question: When the quota is authenticated, what happens if the source port is not specified?

Answer: When the switch does not support the configuration of the souce-interface.

By default, it will correspond to the server. The address corresponding to the port is used as the NAS ip.

Therefore, when you fill in the switch ip address, you should also write this address.

4. between the questions: direct ping nowhere

Answer: 1, both sides can learn arp

(1) The line card version is inconsistent (2) network loop, (3) pinging is prohibited for devices

2. One end can learn ARP, the end can't learn ARP, one end is trunk, one end is access

5. Question: Is the minimalist DOT1X authentication push su unsuccessful?

Answer: When configuring the URL, the ip address of the url is the ip address of the portal. It is not the IP address of the push service. To keep the push and maintenance of the portal, the redirect interface cannot be used. 

6, problem: the switch cannot learn the peer's mac address

Answer: 1. Peer connection error

2. There is a problem with the chip of the switch.

3. Parity issue

The general chip problem is a hardware problem, there is no way to check it. If it is a parity problem, it can be solved by restarting. But Restart is useless, it means hardware problems that need to be repaired.

7, problem: voice and video communications that the same network segment is normal. Is the different network segments only sound no video?

Answer: There is a problem with the dialogue software, the other party solves after upgrading and has nothing to do with the switch (guarantee the forwarding layer is no problem)

8. Question: Is the traffic first going to the gateway or the security device ONC first?

Answer: It is the first hit the flow table and go to the firewall which is the limit we said before.

The traffic that enters the firewall is not the packet after the route. It is the packet before the route.

The message returned in the reverse direction enters the firewall.

Because the firewall device has opened a MAC or VLAN-based check, it will cause the drainage to fail.

So take the security device first, then go to the gateway

9.Problem: OSPF is enabled on the two devices. Link aggregation is used in the middle. The route learning is normal. The neighbor relationship is normal but the pin is pinned. Not a destination address?

Answer: Link aggregation can be broken and tested. Ensure that there are no problems with the aggregated link, modify the load balancing mode or use dynamic aggregation mode.

10.Problem: VRRP is configured on IPV6. Can VRRP fail to be established?

Answer: With the normal configuration of IPV4 the RRP is the same. You need to configure the virtual gateway address of the local IPV6 link address before configuring the virtual gateway. The virtual gateway of the VRRP group in IPV6 can be configured.

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