One day, I contacted a colleague on the first floor via WeChat to use the network cable socket network cable of the workstation to cascade a switch, and asked how?
inform:
1. Create a vlan xxx on the switch and activate it, and use switchport access vlan xxx for the gi ports used
2. Check the cascade port show int gi xx con to view the configuration of the relevant interface
3. Check whether the mac address of each port is in the corresponding vlan, show mac-address all gi xx, the cascade port should be able to see that all devices of the upper-level switch have the mac address of the broadcast message, and the port of the downstream device should be able to see Go to the mac address of the next device, and it is in the same vlan.
Feedback, adding vlan to divide the port is normal, the cascade port shows that the mac is normal, but the device connected to the 12 port has no address, the configured ip192.168.207.35 cannot be pinged, and it shows that the destination host cannot be accessed.
Ask whether port 12 is up on the switch and whether the corresponding LED indicator is lit? Feedback lights up normally. The check status is also up.
It is suspected that there is a problem with the equipment, but no contract has been sent, let it find out the cause of the equipment. Said that it would not be dealt with, let me come down and have a look.
When I went to the site to check, I was connected to a PC with dual network cards, which is used as a network management server, and can log in through the web, and install Linux with a graphical interface.
Switch to the command line shell, ifconfig displays
route -n checks the route is empty, arp -n checks the neighbor mac is empty
Use ip addr | grep LOWER_UP to check which physical network card has a carrier. It is found that enp4s0 without ip has a carrier, but enp1s0 with ip has no carrier. After connecting the network cable to another network card, query:
route -n shows that there are, arp -n shows that there are mac neighbors
ping access, normal, problem solved
Conclusion: The network card is not configured with ip, no packets will be sent out, and there is no mac address on the switch.
ip addr | grep LOWER_UP to check whether the network port has a carrier?
The network card is configured with an ip. After the physical state is activated, the direct route is generated up. When configuring the gateway, the mac address of the gateway will be requested. If there is neighbor access, the neighbor mac address will be synchronized to the arp table. These can be used to judge whether the normal network card is activated.