Windows 7 / Networking

How to Use the Hosts File

You can use the Hosts file as another name resolution method. You might do this if you know that your DNS server is unavailable or the database is out of date, you need to access a server, and you know the server's IP address. It's also useful when you've recently installed a new server and you want to contact it using a host name before the DNS database is updated.

Although you can typically contact servers using their IP addresses, Web sites often need to be reached using the correct host name, and IP addresses might not work.

Your Hosts file is located at %WinDir%\System32\Drivers\Etc\Hosts. It is a text file, and you can edit it using Notepad. To open the Hosts file, run Notepad using administrative permissions. Then, open the Notepad %WinDir%\System32\Drivers\Etc\Hosts file (it does not have a file extension). To add an entry to the Hosts file to enable name resolution without using DNS, add lines to the bottom of the Hosts file, as demonstrated here for IPv4 and IPv6 addresses.

After updating the Hosts file, you can contact servers by using the host name. When an entry is in the Hosts file, Windows will use the associated IP address without contacting a DNS server. In fact, the only application that bypasses the Hosts file is Nslookup, which always contacts DNS servers directly. Remember to remove entries from the Hosts file after you finish using them; otherwise, you might have name resolution problems later if the server's IP address changes.

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In this tutorial:

  1. Troubleshooting Network Issues
  2. Tools for Troubleshooting
  3. Table-1 Network Troubleshooting Tools
  4. Arp
  5. How to Identify a Problem with the ARP Cacher
  6. How to Clear the ARP Cache
  7. Event Viewer
  8. IPConfig
  9. Nblookup
  10. Nbtstat
  11. Net
  12. How to View Shared Folders on the Local Computer
  13. How to View Shared Folders on Another Computer
  14. Netstat
  15. Network Monitor
  16. Nslookup
  17. Verifying that the Default DNS Server Resolves Correctly
  18. Verifying that a Specific DNS Server Resolves Correctly
  19. Verifying Specific Types of Addresses
  20. Using TCP for DNS Lookups
  21. PathPing
  22. PathPing Output
  23. Routing Loops
  24. Performance Problems
  25. Possible Connectivity Issues
  26. No Connectivity Issues
  27. Performance Monitor
  28. Data Collector Sets
  29. Windows Resource Monitor
  30. Ping
  31. PortQry
  32. Identifying the TCP Port for a Service
  33. Windows 7 Testing Service Connectivity
  34. Determining Available Remote Management Protocols
  35. Why PortQry Is Great
  36. Route
  37. Task Manager
  38. TCPView
  39. Telnet Client
  40. Testing Service Connectivity
  41. Test TCP
  42. Windows Network Diagnostics
  43. The Process of Troubleshooting Network Problems
  44. How to Troubleshoot Network Connectivity Problems
  45. How to Troubleshoot Application Connectivity Problems
  46. Default Port Assignments for Common Services and Tasks
  47. How to Troubleshoot Name Resolution Problems
  48. How to Verify Connectivity to a DNS Server
  49. How to Use the Hosts File
  50. How to Troubleshoot Performance Problems and Intermittent Connectivity Issues
  51. How to Troubleshoot Joining or Logging on to a Domain
  52. How to Verify Requirements for Joining a Domain
  53. How to Troubleshoot Network Discovery
  54. How to Troubleshoot File and Printer Sharing
  55. How to Troubleshoot File and Printer Sharing from the Client
  56. How to Troubleshoot File and Printer Sharing from the Server
  57. How to Troubleshoot Wireless Networks
  58. Network Diagnostics
  59. How to Troubleshoot Firewall Problems