diff --git a/docs/using.rst b/docs/using.rst
index 89cbc48f6..909c6eadc 100644
--- a/docs/using.rst
+++ b/docs/using.rst
@@ -31,6 +31,12 @@ In general:
 
 * ``sudo`` is required as a suggested way of running privileged process
 * `swig`_ is required for compiling `m2crypto`_
+
+  .. note:: If your operating system uses SWIG 3.0.5+, you will need
+            to run ``pip install -r requirements-swig-3.0.5.txt -r
+            requirements.txt`` instead of the standard ``pip
+            install -r requirements.txt``.
+
 * `augeas`_ is required for the ``python-augeas`` bindings
 
 
diff --git a/requirements-swig-3.0.5.txt b/requirements-swig-3.0.5.txt
new file mode 100644
index 000000000..9ef45d950
--- /dev/null
+++ b/requirements-swig-3.0.5.txt
@@ -0,0 +1,67 @@
+# Support swig 3.0.5+
+# https://github.com/M2Crypto/M2Crypto/issues/24
+# https://github.com/M2Crypto/M2Crypto/pull/30
+git+https://github.com/M2Crypto/M2Crypto.git@d13a3a46c8934c5f50b31d5f95b23e6e06f845c3#egg=M2Crypto
+
+# This requirements file will fail on Travis CI 12.04 LTS Ubuntu build
+# machine under TOX_ENV=py26 with very confusing error (full tracback
+# at https://api.travis-ci.org/jobs/66529698/log.txt?deansi=true):
+
+#Traceback (most recent call last):
+#  File "setup.py", line 133, in <module>
+#    include_package_data=True,
+#  File "/opt/python/2.6.9/lib/python2.6/distutils/core.py", line 152, in setup
+#    dist.run_commands()
+#  File "/opt/python/2.6.9/lib/python2.6/distutils/dist.py", line 975, in run_commands
+#    self.run_command(cmd)
+#  File "/opt/python/2.6.9/lib/python2.6/distutils/dist.py", line 995, in run_command
+#    cmd_obj.run()
+#  File "/home/travis/build/letsencrypt/lets-encrypt-preview/.tox/py26/lib/python2.6/site-packages/setuptools/command/test.py", line 142, in run
+#    self.with_project_on_sys_path(self.run_tests)
+#  File "/home/travis/build/letsencrypt/lets-encrypt-preview/.tox/py26/lib/python2.6/site-packages/setuptools/command/test.py", line 122, in with_project_on_sys_path
+#    func()
+#  File "/home/travis/build/letsencrypt/lets-encrypt-preview/.tox/py26/lib/python2.6/site-packages/setuptools/command/test.py", line 163, in run_tests
+#    testRunner=self._resolve_as_ep(self.test_runner),
+#  File "/opt/python/2.6.9/lib/python2.6/unittest.py", line 816, in __init__
+#    self.parseArgs(argv)
+#  File "/opt/python/2.6.9/lib/python2.6/unittest.py", line 843, in parseArgs
+#    self.createTests()
+#  File "/opt/python/2.6.9/lib/python2.6/unittest.py", line 849, in createTests
+#    self.module)
+#  File "/opt/python/2.6.9/lib/python2.6/unittest.py", line 613, in loadTestsFromNames
+#    suites = [self.loadTestsFromName(name, module) for name in names]
+#  File "/opt/python/2.6.9/lib/python2.6/unittest.py", line 587, in loadTestsFromName
+#    return self.loadTestsFromModule(obj)
+#  File "/home/travis/build/letsencrypt/lets-encrypt-preview/.tox/py26/lib/python2.6/site-packages/setuptools/command/test.py", line 37, in loadTestsFromModule
+#    tests.append(self.loadTestsFromName(submodule))
+#  File "/opt/python/2.6.9/lib/python2.6/unittest.py", line 584, in loadTestsFromName
+#    parent, obj = obj, getattr(obj, part)
+#AttributeError: 'module' object has no attribute 'continuity_auth'
+
+# the above error happens because letsencrypt.continuity_auth cannot import M2Crypto:
+
+#>>> import M2Crypto
+#Traceback (most recent call last):
+#  File "<stdin>", line 1, in <module>
+#  File "/root/lets-encrypt-preview/venv/lib/python2.6/site-packages/M2Crypto-0.21.1-py2.6-linux-x86_64.egg/M2Crypto/__init__.py", line 22, in <module>
+#    import m2crypto
+#  File "/root/lets-encrypt-preview/venv/lib/python2.6/site-packages/M2Crypto-0.21.1-py2.6-linux-x86_64.egg/M2Crypto/m2crypto.py", line 26, in <module>
+#    _m2crypto = swig_import_helper()
+#  File "/root/lets-encrypt-preview/venv/lib/python2.6/site-packages/M2Crypto-0.21.1-py2.6-linux-x86_64.egg/M2Crypto/m2crypto.py", line 22, in swig_import_helper
+#    _mod = imp.load_module('_m2crypto', fp, pathname, description)
+#ImportError: /root/lets-encrypt-preview/venv/lib/python2.6/site-packages/M2Crypto-0.21.1-py2.6-linux-x86_64.egg/M2Crypto/_m2crypto.so: undefined symbol: SSLv2_method
+
+# For more info see:
+
+# - https://github.com/martinpaljak/M2Crypto/commit/84977c532c2444c5487db57146d81bb68dd5431d
+# - http://stackoverflow.com/questions/10547332/install-m2crypto-on-a-virtualenv-without-system-packages
+# - http://stackoverflow.com/questions/8206546/undefined-symbol-sslv2-method
+
+# In short: Python has been built without SSLv2 support, and
+# github.com/M2Crypto/M2Crypto version doesn't contain necessary
+# patch, but it's the only one that has a patch for newer versions of
+# swig...
+
+# Problem seems not exists on Python 2.7. It's unlikely that the
+# target distribution has swig 3.0.5+ and doesn't have Python 2.7, so
+# this file should only be used in conjuction with Python 2.6.
diff --git a/requirements.txt b/requirements.txt
index 6c2535a9d..0f0223dab 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,9 +1,3 @@
 # https://github.com/bw2/ConfigArgParse/issues/17
 -e git+https://github.com/kuba/ConfigArgParse.git@python2.6#egg=ConfigArgParse
-
-# Support swig 3.0.5
-# https://github.com/M2Crypto/M2Crypto/issues/24
-# https://github.com/M2Crypto/M2Crypto/pull/30
-git+https://github.com/M2Crypto/M2Crypto.git@d13a3a46c8934c5f50b31d5f95b23e6e06f845c3#egg=M2Crypto
-
 -e .