Connect your Mac to the Internet using Ethernet
You can use Ethernet to connect to the Internet, either through an Ethernet network or through a DSL or cable modem. If you’re using a modem, make sure the modem is turned on and connected to the wall jack with the cable that came with the modem.
Use an Ethernet cable to connect your computer’s Ethernet port to a modem or other network device (for example, a switch or a router). If your computer doesn’t have an Ethernet port, try using a USB to Ethernet adapter, or a Thunderbolt to Gigabit Ethernet adapter.
In many cases, you’ll automatically connect to the Internet. If not, complete the following steps to enter your network settings. If you aren’t sure what to enter, check with your network administrator or ISP.
On your Mac, choose Apple menu
> System Preferences, then click Network.Select Ethernet in the list on the left.
Click the Configure IPv4 pop-up menu and choose your ISP’s recommended configuration method.
Using DHCP or Using BootP: Choose one of these if you receive an IP address automatically from your ISP.
Using DHCP with manual address: Choose this if you received a specific IP address and your ISP uses DHCP or other network settings.
Manually: Choose this if you received a specific IP address, a subnet mask, and a router address from your ISP.
Click Advanced, click DNS, click the Add button
under DNS Servers, then enter the IP address of your ISP’s DNS server. If your ISP gave you search domain addresses, enter them as well. These may not be needed if you configure your IP settings to use DHCP.If you were given other settings from your service provider, such as IPv6, proxy server, or additional Ethernet settings, click Advanced to enter them.
Click OK to make the settings active for the Ethernet service.