LMHOSTS File: Definition, Examples


An LMHOSTS file is a text file used by Microsoft Windows to map NetBIOS names to specific IP addresses. It acts like a manual Domain Name System for the server or host, allowing name resolution without requiring a name server. The file is typically used in networks where DNS isn’t available.


The phonetics for “LMHOSTS File” would be “el-em-hosts fahyl”.

Key Takeaways

  1. Configuration of Network Names: The LMHOSTS file is used to map IP addresses to network names. It makes the translation between these two, especially when the network is unable to perform automatic name resolution or when you want to create custom names for particular IP addresses.
  2. Operate in Windows Environment: This file is part of the Microsoft Windows operating system. Its main application is in the Windows Networking environment, where it enables the NetBIOS names of networked computers to be resolved into IP addresses, even when DNS isn’t available.
  3. Manual Management: It’s a plain text file, and thus, can be manually edited using any simple text editor. However, care must be given to the changes made in this file due to its crucial role in the network. Mistakes in entries or syntax can lead to networking issues.


The LMHOSTS file is a crucial aspect of technology systems as it aids in the mapping of IP addresses to NetBIOS names of networked devices, typically in a Microsoft Windows environment. This is important because it allows users and applications to access remote systems by using their NetBIOS name instead of their IP address, making network navigation easier and more user-friendly. Without the LMHOSTS file, users would need to memorize or constantly look up complex IP addresses. Moreover, it plays a significant role in environments where the WINS server might fail or is not feasible, providing necessary redundancy and network resilience. Hence, the LMHOSTS file serves as a vital component to ensure seamless network accessibility and communication.


The LMHOSTS file is a mechanism that assists in the resolution of NetBIOS to specific IP addresses in a local area network (LAN) environment. The primary purpose and utilization of the LMHOSTS file comes into play in scenarios where a DNS server is either not available or functional, or when the computer names in the network are not registered with a DNS server. In such cases, the LMHOSTS file aids in facilitating communication between networked computers by mapping NetBIOS names to static IP addresses.It’s noteworthy that the LMHOSTS file is a purely local method of name resolution and does not propagate or replicate like a DNS server does. Each computer in the network has a locally stored LMHOSTS file where the mappings of computer names to IP addresses are stored. This means that an individual LMHOSTS file must be manually updated on each computer when there’s a change in the network configuration. Though this method can be labor-intensive in larger networks, the LMHOSTS file provides a reliable and simple solution for name resolution in smaller networks where a DNS server might not be necessary or affordable.


1. Home Networking: In a home or small business network setup, users often have a handful of computers they frequently share resources with (files, printers, etc.). A LMHOSTS file allows the user to map IP addresses to these easy-to-remember names in their small local network. For instance, a PC named “Office PC” might be assigned an IP address of within the LMHOSTS file so that other computers in the network can connect to it by simply using its name.2. Corporate Networks: In a large corporation, where there are numerous computers and servers, LMHOSTS file is used to resolve computer names to IP addresses. The IT department often uses the LMHOSTS files when they don’t want to use a DNS (Domain Name System) or WINS (Windows Internet Naming Service) server for name resolution, typically due to security reasons. 3. Testing and Debugging: Software developers and network administrators often use LMHOSTS files when creating and troubleshooting networked applications. By manually editing the file, they can control the IP address to which a computer name resolves, this helps them simulate different networking scenarios and interactions between systems under controlled conditions.

Frequently Asked Questions(FAQ)

**Q1: What is an LMHOSTS File?**A1: The LMHOSTS or ‘Local Machine Hosts’ file is a file in the Microsoft Windows operating system that maps IP addresses to NETBIOS names of remote servers with which a computer wishes to communicate in a small network. It helps in the protocol called NetBIOS over TCP/IP which involves communication between computers on different networks.**Q2: What is the importance of the LMHOSTS File?**A2: LMHOSTS file is important for enabling name resolution in networks without local domain name system (DNS) servers. It provides a method for naming devices or hosts and their respective IP addresses, making it easier for the system to find them.**Q3: Where is LMHOSTS File stored in my computer?**A3: In Microsoft Windows, the LMHOSTS file is usually stored in the C:\Windows\System32\drivers\etc directory.**Q4: Can I modify the LMHOSTS file?**A4: Yes, you can modify the LMHOSTS file using any text editor. However, it requires administrative privileges for changes to take effect, and any incorrect modifications can cause network communication issues.**Q5: How is DNS different from LMHOSTS?**A5: DNS or Domain Name System is a system used to translate domain names to IP addresses on the internet. On the other hand, LMHOSTS is a local method for resolving NetBIOS names to IP addresses and is typically used in smaller networks or in absence of a DNS server.**Q6: What is the format of LMHOSTS file?**A6: An entry in the LMHOSTS file has the format IP address (space) hostname. Comments can also be added in an LMHOSTS file after the hostname, starting with a ‘#’ symbol.**Q7: Why am I unable to edit the LMHOSTS file?**A7: You might be unable to edit the LMHOSTS file because it requires administrative privileges. Ensure that you are logged in as an administrator before trying to make changes to this file.**Q8: Can I delete the LMHOSTS file?**A8: While it is technically possible to delete the LMHOSTS file, doing so could disrupt network communication services on your computer. It is generally advised to leave system files, such as the LMHOSTS file, intact unless you fully understand the consequences.

Related Tech Terms

  • NetBIOS
  • Hostname Resolution
  • Windows Networking
  • IP Addressing
  • Local Network

Sources for More Information


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