To the last, I talked with a Mac friend of mine. He gave me a list of steps he found somewhere on the Internet.
1. From the Apple menu, choose System Preferences
2. Click the Network icon
3. Click the arrow box on the Show pop-up list and chooseBuilt-in Ethernet
4. Click on the PPPoE tab
5. Check the box next to Connect using PPPoE
6. In the Account Name field, type your email address
7. In the Password field, type your password
8. Check the box next to Save password
9. Check the boxnext to Show PPPoE status in menu bar
10. Click the PPPoE Options button
11. Check the box next to Connect automatically when starting TCP/IP applications
12. Uncheck the box next to Prompt to stay connected if idle for X minutes
13. Uncheck thebox next to Disconnect if idle for X minutes
14. Check the box next to Disconnect when user logs out
15. Click the OK button
16. Click on the TCP/IP tab
17. Click the arrow box on the Configure pop-up list and choose Using PPP
18. In the DomainName Servers box, type the DNS server addresses for your domain
19. In the Search Domains box, type your domain
Note: In some areas the Domain Name Servers and Search Domain may not have to be specified. Clear these fields if you are unable to browse.
20. Click the Apply Now button
21. Close the Network window
22. From the Apple menu, choose Restart