Environment description:
Virtualization platform: vmare5.5
Physical machine system: esxi
Virtual machine: centos7.5
2 switches: Ruijie and Huawei
Cabinet location –> The switch above is Huawei’s
26 cabinet, 1 physical machine IP
10.1.1.1
Cabinet location –> The switches above are Ruijie’s
12 cabinets and 3 physical machines. IP
10.1.1.2
10.1.1.3
10.1.1.4
There are 2 network cables plugged into the physical machine.
Network cable a is the physical machine-management network 10.1.1.2.
Network cable b is assigned vlan120 and the network segment is 20.0.0.1/24.
Problem:
The virtual machine in the vlan120 network segment built with 3 physical machines in 12 cabinets cannot ping the gateway.
Step 1: We initially suspected that there was a problem with the switch. We asked our colleagues on the network to check whether the switch was normal. The colleagues on the network also checked the configuration and said it was normal. We directly plugged the network cable into the switch and connected it to the laptop. After modifying the vlan120 network segment, pinging the gateway was normal. ;Give feedback that the switch is normal;
I myself plugged the network cable of the Ruijie switch in the 12th cabinet into other cabinets for physical testing. After configuring the vlan120 network segment, pinging the gateway was normal.
Step 2: It is suspected that there is a problem with the virtual switch at the vmare level. I can't see any abnormalities when I change the configuration of the virtual machine. Later, I asked colleagues from the company who specialize in the vmare platform to provide remote assistance and test adjustments, but no abnormalities were found;
After repeated tossing and discussion, I finally figured out whether the server's network card was broken, and then called the server manufacturer to ask the server manufacturer to replace the network card for free.
Step 3: Ask the manufacturer to change the network card and continue testing, but it still doesn’t work;
Step 4: While the manufacturer was replacing the network card, I recalled the idea I had last night; connect a cable from the switch on cabinet 26 and plug it into cabinet 12 to test vlan120 to see if there is a problem with the switch configuration; I found a few cables Network cable, add network cable splicer, finally plugged in the network cable, pinged the gateway, okay! ! ! Finally I found out that it was a switch configuration problem.
Step 5: Coordinate the network to modify the switch configuration. The original configuration was access mode.
The 12-cabinet physical machine corresponds to ports 24, 25, and 26 behind the switch. It is changed to trunk mode and the test is normal;
The difference between switch VLAN mode trunk and access
mode. The access mode can only carry the traffic of one VLAN.
The trunk port can allow data packets of multiple VLANs to pass through.