Pre-standardisation program "/etc/hosts" file format, Cloud and AI new issues IETF#10088

Question

My name is Loic Coupel, and I would like to raise an issue regarding the /etc/hosts file format across all operating systems: Linux, Windows, and macOS.

After working in IT support for many years, I have observed that many IT engineers create incorrectly formatted files; often with duplicate IPs or multiple FQDNs even in cloud environments and large organisations.

This can cause applications to fail, spike CPU and memory usage, and produce unpredictable network behaviour. Please note that /etc/hosts is always read before DNS, so errors in the file can block communication without clear error messages.

Default formats differ between distributions (e.g., Red Hat/Mageia vs Debian) and other OSes, and there is currently no universally enforced standard.

I request that a meeting be organised between representatives of all responsible OS teams to discuss this issue.

This problem affects system reliability and performance, with broader implications for sustainability and environmental impact, as well as electronic ship crisis.

I have contacted the IETF and IEEE instance

can I have someone that would be able to follow the subject on this from Microsoft ?

Answer 1

You are correct that inconsistencies in /etc/hosts formatting across operating systems can lead to unpredictable behavior, and we appreciate your initiative in contacting standards bodies such as the IETF and IEEE. At Microsoft, while we actively participate in industry-wide standards discussions, requests for formal engagement on cross-vendor topics like this are best directed through established standards organizations. This ensures that all stakeholders - including Linux distributions, Apple, and Microsoft - can collaborate in a structured and transparent way.

I recommend continuing your dialogue with the IETF and IEEE, as they are the appropriate forums to convene representatives from multiple OS vendors. If a working group is formed, Microsoft would evaluate participation through our standards engagement channels. In the meantime, I encourage documenting specific cases where misconfigured /etc/hosts files have impacted system reliability, as concrete examples often help standards bodies prioritize issues.

If this guidance helps clarify the next steps, please consider hitting “Accept Answer” 🙂, it’s always appreciated!

Harry.

Answer 2

I have created the following thread GIT at IETF group

https://github.com/ietf-tools/datatracker/issues/10088

please do not hesitate to go and do follow up

Answer 3

I have created the following thread GIT

https://github.com/ietf-tools/datatracker/issues/10088

please do not hesitate to go and do follow up

Answer 4

The issue you've raised regarding the formatting of the /etc/hosts file across different operating systems is indeed significant. As you noted, inconsistencies in the format can lead to various operational problems, including application failures and unpredictable network behavior. This is particularly critical since the /etc/hosts file is consulted before DNS, meaning that errors can disrupt communication without clear indications of the problem.

Currently, there isn't a universally enforced standard for the /etc/hosts file format, which can vary between different Linux distributions, Windows, and macOS. This lack of standardization can lead to the issues you've observed in IT environments, especially in large organizations and cloud settings.

While I cannot facilitate a meeting or provide direct contact with Microsoft representatives, I recommend reaching out to Microsoft support or their developer community forums for further assistance on this matter. They may be able to connect you with someone who can address your concerns more directly.

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References:

• Working with /etc/hosts file using Azure IoT and OSConfig
• What is OSConfig for Linux devices?