The RabbitMQ docs state ([1]): RabbitMQ nodes and CLI tools (e.g. rabbitmqctl) use a cookie to determine whether they are allowed to communicate with each other. [...] The cookie is just a string of alphanumeric characters up to 255 characters in size. It is usually stored in a local file. ...and goes on to state (emphasis ours): If the file does not exist, Erlang VM will try to create one with a randomly generated value when the RabbitMQ server starts up. Using such generated cookie files are **appropriate in development environments only.** The auto-generated cookie does not use cryptographic sources of randomness, and generates 20 characters of `[A-Z]`. Because of a semi-predictable seed, the entropy of this password is thus less than the idealized 26^20 = 94 bits of entropy; in actuality, it is 36 bits of entropy, or potentially as low as 20 if the performance of the server is known. These sizes are well within the scope of remote brute-force attacks. On provision, install, and upgrade, replace the default insecure 20-character Erlang cookie with a cryptographically secure 255-character string (the max length allowed). [1] https://www.rabbitmq.com/clustering.html#erlang-cookie
Zulip overview
Zulip is a powerful, open source group chat application that combines the immediacy of real-time chat with the productivity benefits of threaded conversations. Zulip is used by open source projects, Fortune 500 companies, large standards bodies, and others who need a real-time chat system that allows users to easily process hundreds or thousands of messages a day. With over 700 contributors merging over 500 commits a month, Zulip is also the largest and fastest growing open source group chat project.
Getting started
Click on the appropriate link below. If nothing seems to apply, join us on the Zulip community server and tell us what's up!
You might be interested in:
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Contributing code. Check out our guide for new contributors to get started. Zulip prides itself on maintaining a clean and well-tested codebase, and a stock of hundreds of beginner-friendly issues.
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Contributing non-code. Report an issue, translate Zulip into your language, write for the Zulip blog, or give us feedback. We would love to hear from you, even if you're just trying the product out.
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Supporting Zulip. Advocate for your organization to use Zulip, become a sponsor, write a review in the mobile app stores, or upvote Zulip on product comparison sites.
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Checking Zulip out. The best way to see Zulip in action is to drop by the Zulip community server. We also recommend reading Zulip for open source, Zulip for companies, or Zulip for working groups and part time communities.
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Running a Zulip server. Use a preconfigured DigitalOcean droplet, install Zulip directly, or use Zulip's experimental Docker image. Commercial support is available; see https://zulip.com/plans for details.
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Using Zulip without setting up a server. https://zulip.com offers free and commercial hosting, including providing our paid plan for free to fellow open source projects.
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Participating in outreach programs like Google Summer of Code.
You may also be interested in reading our blog or following us on Twitter. Zulip is distributed under the Apache 2.0 license.