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pycares: Python interface for c-ares

pycares is a Python module which provides an interface to c-ares. c-ares is a C library that performs DNS requests and name resolutions asynchronously.


Bundled c-ares

pycares currently bundles c-ares and as of pycares 1.0.0 this is a strong requirement. Upstream c-ares is not willing to apply a patch adding TTL support. I did apply the patch to the bundled c-ares, but unfortunately it breaks the ABI, so attempting to use a system provided c-ares is not possible.


GNU/Linux, macOS, Windows, others:

pip install pycares


cd /usr/ports/dns/py-pycares && make install

IDNA 2008 support

If the idna package is installed, pycares will support IDNA 2008 encodingm otherwise the builtin idna codec will be used, which provides IDNA 2003 support.

You can force this at installation time as follows:

pip install pycares[idna]

Running the test suite

There are several ways of running the test ruite:

  • Run the test with the current Python interpreter:

    From the toplevel directory, run: python tests/

  • Use Tox to run the test suite in several virtualenvs with several interpreters

    From the toplevel directory, run: tox -e py35,py36,py37 this will run the test suite on Python 3.5, 3.6 and 3.7 (you'll need to have them installed beforehand)

Using it from the cli, a la dig

This module can be used directly from the command line in a similar fashion to dig (limited, of course):

$ python -m pycares
;                  IN      A

;; ANSWER SECTION:           300     IN      A

$ python -m pycares mx
;                  IN      MX

;; ANSWER SECTION:           600     IN      MX      50           600     IN      MX      10           600     IN      MX      40           600     IN      MX      20           600     IN      MX      30


Saúl Ibarra Corretgé <>


Unless stated otherwise on-file pycares uses the MIT license, check LICENSE file.

Supported Python versions

Python >= 3.5 are supported. Both CPython and PyPy are supported.


If you'd like to contribute, fork the project, make a patch and send a pull request. Have a look at the surrounding code and please, make yours look alike :-)

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