Enter proxy server settings
If your computer is connected to a local network that’s protected from the Internet by a firewall, you may need to specify proxy servers or use the FTP passive mode (PASV) to access some Internet sites. A proxy server is a computer on a local network that acts as an intermediary between a single computer user and the Internet so that the network can ensure security, administrative control, and caching service.
Choose Apple menu > System Preferences, then click Network.
Select the network service you use in the list—for example, Ethernet or Wi-Fi.
Click Advanced, then click Proxies.
If you configure your proxy server settings automatically, select Auto Proxy Discovery to automatically discover proxy servers, or select Automatic Proxy Configuration if you’re using a proxy auto-configuration (PAC) file. If you select Automatic Proxy Configuration, enter the address of the PAC file in the URL field. Check with your network administrator if you need more information.
If you configure your proxy settings manually, do the following:
Select a proxy server, such as FTP Proxy, then type its address and port number in the fields on the right.
Select the “Proxy server requires password” checkbox if the proxy server is protected by a password. Enter your account name and password in the Username and Password fields.
You can also choose to bypass proxy settings for specific computers on the Internet (hosts) and segments of the Internet (domains) by adding the address of the host or domain in the “Bypass proxy settings for these Hosts & Domains” field. This might be useful if you want to make sure you’re receiving information directly from the host or domain and not information that’s cached on the proxy server.
To bypass a single domain, enter the domain name—for example, apple.com.
To bypass all websites on a domain, use an asterisk before the domain name—for example, *apple.com.
To bypass a specific part of a domain, specify each part—for example, store.apple.com.