On 04/17/2016 07:39 PM, liyulei wrote: > Could anybody teach me how to create a VLAN interface in CentOS7, or tell me > what' s wrong with my configuration, more detailed more better. How is your switch configured? The CentOS configuration you described would only work when you set GATEWAY, and when the port it's connected to has no VLANs configured for untagged access (or no VLANs that you need to access), and when the VLAN you DO need to access is tagged. Are you providing access to one VLAN using tagged packets?