# Technical Inquiry: Support for /31 Subnet Mask on Replication Network (DRBD & WinDRBD)

**URL:** <https://forums.linbit.com/t/technical-inquiry-support-for-31-subnet-mask-on-replication-network-drbd-windrbd/1211>\
**Category:** DRBD\
**Tags:** drbd\
**Created:** [April 27, 2026, 8:18am UTC](https://forums.linbit.com/t/technical-inquiry-support-for-31-subnet-mask-on-replication-network-drbd-windrbd/1211 "2026-04-27T08:18:56Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![inyoung](https://avatars.discourse-cdn.com/v4/letter/i/9e8a1a/32.png) [@inyoung](https://forums.linbit.com/u/inyoung)\
**Post date:** [April 27, 2026, 8:18am UTC](https://forums.linbit.com/t/technical-inquiry-support-for-31-subnet-mask-on-replication-network-drbd-windrbd/1211/1 "2026-04-27T08:18:56Z")

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I am writing to inquire about the network configuration requirements for DRBD in a High Availability (HA) setup.

We are planning to configure a dedicated private network for data mirroring between two nodes. To optimize IP address utilization, we intend to use a **31-bit subnet mask (/31, RFC 3021)** for this point-to-point connection.

1. Are there any known issues or limitations when using a /31 subnet mask for DRBD (Linux) and WinDRBD (Windows) replication traffic?

We look forward to your professional guidance on this matter.

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**Author:** ![michael](https://yyz1.discourse-cdn.com/flex003/user_avatar/forums.linbit.com/michael/32/16_2.png) [@michael](https://forums.linbit.com/u/michael)\
**Post date:** [April 30, 2026, 12:20pm UTC](https://forums.linbit.com/t/technical-inquiry-support-for-31-subnet-mask-on-replication-network-drbd-windrbd/1211/2 "2026-04-30T12:20:38Z")

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To speak to part of your question, the LINBIT knowledge base article, [“LINSTOR and DRBD Hardware Considerations”](https://kb.linbit.com/linstor/linstor-and-drbd-hardware-considerations/), describes some hardware considerations when using LINSTOR or DRBD, including networking hardware.

It is a general overview article but perhaps it can get you started.

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**Author:** ![inyoung](https://avatars.discourse-cdn.com/v4/letter/i/9e8a1a/32.png) [@inyoung](https://forums.linbit.com/u/inyoung)\
**Post date:** [May 5, 2026, 11:58pm UTC](https://forums.linbit.com/t/technical-inquiry-support-for-31-subnet-mask-on-replication-network-drbd-windrbd/1211/3 "2026-05-05T23:58:53Z")

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Thank you for your reply.

I will check the link you sent.

Thank you for your help.🙂