ISC (Internet Systems Consortium )License: A Comprehensive Guide

In the vast landscape of open-source licenses, the Internet Systems Consortium License (ISC) stands out for its simplicity and permissiveness. ISC is a widely-used license that promotes free software distribution, while ensuring minimal restrictions on usage and modification. In this in-depth article, we will explore the ISC License, its key features, and its implications for developers and users. Let’s dive into the details of ISC and understand why it is a preferred choice in the open-source community.

What is the ISC License?

The ISC License, also known as the Internet Software Consortium License, is a permissive open-source license that originated from the Internet Systems Consortium (ISC). ISC is a non-profit organization that develops and maintains several critical internet infrastructure software, including the BIND DNS server and the DHCP server.

Key Features of ISC License:

  1. Simple and Concise:
    The ISC License is renowned for its simplicity and brevity. Unlike some other open-source licenses, the ISC License consists of only a few lines of clear and easy-to-understand text. This simplicity facilitates ease of adoption and interpretation, making it an attractive choice for developers seeking minimal legal complexities.
  2. Permissive Usage Rights:
    ISC grants users extensive freedom to use, modify, and distribute the software covered by the license. Users are not bound by any specific usage restrictions, allowing them to utilize the software in commercial, non-commercial, or private projects without facing licensing hurdles.
  3. No Copyleft Provision:
    Unlike the GNU General Public License (GPL) or GNU Affero General Public License (AGPL), the ISC License does not include copyleft provisions that require derivative works to be distributed under the same license. This means that developers can choose to combine ISC-licensed code with code under other licenses, even proprietary licenses, without triggering license compatibility issues.
  4. Redistribution and Attribution:
    The ISC License requires that any redistribution of the software must include a copy of the original license and copyright notice. While users are not obligated to provide attribution to the original authors, including the copyright notice acknowledges their contributions and maintains transparency in the open-source community.
  5. No Warranty:
    Similar to most open-source licenses, the ISC License disclaims any warranty or liability, placing the responsibility on the users and redistributors of the software. Developers should be aware that the software is provided “as is” without any guarantee of performance or fitness for a specific purpose.

Implications for Developers and Users:

For Developers:

  • Choosing ISC: Developers who prefer a simple and permissive license without copyleft restrictions may opt for the ISC License. ISC enables unrestricted use and redistribution of the code, encouraging collaboration and widespread adoption.
  • Code Inclusion: ISC-licensed code can be seamlessly integrated into proprietary projects or other open-source projects without causing licensing conflicts. This flexibility allows developers to contribute code to a diverse range of projects.

For Users:

  • Freedom of Use: Users of ISC-licensed software enjoy the liberty to utilize the code for any purpose, be it personal, commercial, or academic, without seeking additional permissions.
  • Redistribution: The ISC License facilitates the redistribution of software without cumbersome legal processes, making it attractive for downstream users who want to share the code with others.


The Internet Systems Consortium License (ISC) is a straightforward and permissive open-source license that offers developers and users tremendous freedom and flexibility. Its simplicity, coupled with minimal restrictions, makes it a preferred choice for many projects within the open-source community. By adopting the ISC License, developers contribute to the ethos of open-source development, encouraging collaboration and innovation across the internet landscape.

Whether you’re a developer seeking a license for your software or a user looking to leverage ISC-licensed projects, understanding the implications and benefits of the ISC License empowers you to make informed decisions in the dynamic world of open-source software. Embrace the spirit of ISC, foster collaboration, and contribute to the thriving open-source ecosystem.

If you’re interested in exploring a comprehensive list of various open-source licenses and their details, feel free to check out our guide to “Open Source Licenses : A Guide To Software Licensing“. Happy licensing!


  1. Internet Systems Consortium License (ISC). (n.d.). Internet Systems Consortium.
  2. The Open Source Initiative. (n.d.). The ISC License.
  3. Internet Systems Consortium. (n.d.). ISC Software Licenses.

Please note that the information provided in this article is for general reference purposes only. It is essential to read and understand the full text of the Internet Systems Consortium License (ISC) and any other licenses before using or redistributing any software covered by these licenses.

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