pip安装失败，并显示“连接错误：[SSL：CERTIFICATE_VERIFY_FAILED]证书验证失败（_ssl.c：598）”

I am very new to Python and trying to > pip install linkchecker on Windows 7. Some notes:

• pip install is failing no matter the package. For example, > pip install scrapy also results in the SSL error.
• Vanilla install of Python 3.4.1 included pip 1.5.6. The first thing I tried to do was install linkchecker. Python 2.7 was already installed, it came with ArcGIS. python and pip were not available from the command line until I installed 3.4.1.
• > pip search linkchecker works. Perhaps that is because pip search does not verify the site’s SSL certificate.
• I am in a company network but we do not go through a proxy to reach the Internet.
• Each company computer (including mine) has a Trusted Root Certificate Authority that is used for various reasons including enabling monitoring TLS traffic to https://google.com. Not sure if that has anything to do with it.

Here are the contents of my pip.log after running pip install linkchecker:

Downloading/unpacking linkchecker
  Getting page https://pypi.python.org/simple/linkchecker/
  Could not fetch URL https://pypi.python.org/simple/linkchecker/: connection error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:598)
  Will skip URL https://pypi.python.org/simple/linkchecker/ when looking for download links for linkchecker
  Getting page https://pypi.python.org/simple/
  Could not fetch URL https://pypi.python.org/simple/: connection error: HTTPSConnectionPool(host='pypi.python.org', port=443): Max retries exceeded with url: /simple/ (Caused by <class 'http.client.CannotSendRequest'>: Request-sent)
  Will skip URL https://pypi.python.org/simple/ when looking for download links for linkchecker
  Cannot fetch index base URL https://pypi.python.org/simple/
  URLs to search for versions for linkchecker:
  * https://pypi.python.org/simple/linkchecker/
  Getting page https://pypi.python.org/simple/linkchecker/
  Could not fetch URL https://pypi.python.org/simple/linkchecker/: connection error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:598)
  Will skip URL https://pypi.python.org/simple/linkchecker/ when looking for download links for linkchecker
  Could not find any downloads that satisfy the requirement linkchecker
Cleaning up...
  Removing temporary dir C:\Users\jcook\AppData\Local\Temp\pip_build_jcook...
No distributions at all found for linkchecker
Exception information:
Traceback (most recent call last):
  File "C:\Python34\lib\site-packages\pip\basecommand.py", line 122, in main
    status = self.run(options, args)
  File "C:\Python34\lib\site-packages\pip\commands\install.py", line 278, in run
    requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)
  File "C:\Python34\lib\site-packages\pip\req.py", line 1177, in prepare_files
    url = finder.find_requirement(req_to_install, upgrade=self.upgrade)
  File "C:\Python34\lib\site-packages\pip\index.py", line 277, in find_requirement
    raise DistributionNotFound('No distributions at all found for %s' % req)
pip.exceptions.DistributionNotFound: No distributions at all found for linkchecker

—–> pip install gensim config –global http.sslVerify false

Just install any package with the “config –global http.sslVerify false” statement

You can ignore SSL errors by setting pypi.org and files.pythonhosted.org as trusted hosts.

$ pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org <package_name>

Note: Sometime during April 2018, the Python Package Index was migrated from pypi.python.org to pypi.org. This means “trusted-host” commands using the old domain no longer work.

Permanent Fix

Since the release of pip 10.0, you should be able to fix this permanently just by upgrading pip itself:

$ pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org pip setuptools

Or by just reinstalling it to get the latest version:

$ curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

(… and then running get-pip.py with the relevant Python interpreter).

pip install <otherpackage> should just work after this. If not, then you will need to do more, as explained below.

You may want to add the trusted hosts and proxy to your config file.

pip.ini (Windows) or pip.conf (unix)

[global]
trusted-host = pypi.python.org
               pypi.org
               files.pythonhosted.org

Alternate Solutions (Less secure)

Most of the answers could pose a security issue.

Two of the workarounds that help in installing most of the python packages with ease would be:

• Using easy_install: if you are really lazy and don’t want to waste much time, use easy_install <package_name>. Note that some packages won’t be found or will give small errors.
• Using Wheel: download the Wheel of the python package and use the pip command pip install wheel_package_name.whl to install the package.

You can specify a cert with this param:

pip --cert /etc/ssl/certs/FOO_Root_CA.pem install linkchecker

See: Docs » Reference Guide » pip

If specifying your company’s root cert doesn’t work maybe the cURL one will work: http://curl.haxx.se/ca/cacert.pem

You must use a PEM file and not a CRT file. If you have a CRT file you will need to convert the file to PEM There are reports in the comments that this now works with a CRT file but I have not verified.

Also check: SSL Cert Verification.

kenorb’s answer is very useful (and great!).
Among his solutions, maybe this is the most simple one: --trusted-host

For example, in this case you can do

pip install --trusted-host pypi.python.org linkchecker

The pem file(or anything else) is unnecessary.

For me the problem was fixed by creating a folder pip, with a file: pip.ini in C:\Users\<username>\AppData\Roaming\ e.g:

C:\Users\<username>\AppData\Roaming\pip\pip.ini

Inside it I wrote:

[global]
trusted-host = pypi.python.org
               pypi.org
               files.pythonhosted.org

I restarted python, and then pip permanently trusted these sites, and used them to download packages from.

If you can’t find the AppData Folder on windows, write %appdata% in file explorer and it should appear.

The answers are quite similar and a bit confusing. In my case, the certificates in my company’s network was the issue. I was able to work around the problem using:

pip install --trusted-host files.pythonhosted.org --trusted-host pypi.org --trusted-host pypi.python.org oauthlib -vvv

As seen here. The -vvv argument can be omited if verbose output is not required

Permanent Fix

pip install --upgrade pip --trusted-host pypi.org --trusted-host files.pythonhosted.org

For eg:

pip install <package name> --trusted-host pypi.org --trusted-host files.pythonhosted.org

To solve this problem once and for all, you can verify that you have a pip.conf file.

This is where your pip.conf should be, according to the documentation:

On Unix the default configuration file is: $HOME/.config/pip/pip.conf which respects the XDG_CONFIG_HOME environment variable.

On macOS the configuration file is $HOME/Library/Application Support/pip/pip.conf if directory $HOME/Library/Application Support/pip exists else $HOME/.config/pip/pip.conf

On Windows the configuration file is %APPDATA%\pip\pip.ini.

Inside a virtualenv:

On Unix and macOS the file is $VIRTUAL_ENV/pip.conf

On Windows the file is: %VIRTUAL_ENV%\pip.ini

Your pip.conf should look like:

[global]
trusted-host = pypi.python.org

pip install linkchecker installed linkchecker without complains after I created the pip.conf file.

The most straightforward way I’ve found, is to download and use the “DigiCert High Assurance EV Root CA” from DigiCert at https://www.digicert.com/digicert-root-certificates.htm#roots

You can visit https://pypi.python.org/ to verify the cert issuer by clicking on the lock icon in the address bar, or increase your geek cred by using openssl:

$ openssl s_client -connect pypi.python.org:443
CONNECTED(00000003)
depth=1 /C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert SHA2 Extended Validation Server CA
verify error:num=20:unable to get local issuer certificate
verify return:0
---
Certificate chain
 0 s:/businessCategory=Private Organization/1.3.6.1.4.1.311.60.2.1.3=US/1.3.6.1.4.1.311.60.2.1.2=Delaware/serialNumber=3359300/street=16 Allen Rd/postalCode=03894-4801/C=US/ST=NH/L=Wolfeboro,/O=Python Software Foundation/CN=www.python.org
   i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert SHA2 Extended Validation Server CA
 1 s:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert SHA2 Extended Validation Server CA
   i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance EV Root CA

The last CN value in the certificate chain is the name of the CA that you need to download.

For a one-off effort, do the following:

1. Download the CRT from DigiCert
2. Convert the CRT to PEM format
3. Export the PIP_CERT environment variable to the path of the PEM file

(the last line assumes you are using the bash shell) before running pip.

curl -sO http://cacerts.digicert.com/DigiCertHighAssuranceEVRootCA.crt 
openssl x509 -inform DES -in DigiCertHighAssuranceEVRootCA.crt -out DigiCertHighAssuranceEVRootCA.pem -text
export PIP_CERT=`pwd`/DigiCertHighAssuranceEVRootCA.pem

To make this re-usable, put DigiCertHighAssuranceEVRootCA.crt somewhere common and export PIP_CERT accordingly in your ~/.bashrc.

You’ve the following possibilities to solve issue with CERTIFICATE_VERIFY_FAILED:

• Use HTTP instead of HTTPS (e.g. --index-url=http://pypi.python.org/simple/).

• Use --cert <trusted.pem> or CA_BUNDLE variable to specify alternative CA bundle.

  E.g. you can go to failing URL from web-browser and import root certificate into your system.

• Run python -c "import ssl; print(ssl.get_default_verify_paths())" to check the current one (validate if exists).

• OpenSSL has a pair of environments (SSL_CERT_DIR, SSL_CERT_FILE) which can be used to specify different certificate database^PEP-476.
• Use --trusted-host <hostname> to mark the host as trusted.
• In Python use verify=False for requests.get (see: SSL Cert Verification).
• Use --proxy <proxy> to avoid certificate checks.

Read more at: TLS/SSL wrapper for socket objects – Verifying certificates.

Set Time and Date correct!

For me, it came out that my date and time was misconfigured on Raspberry Pi. The result was that all SSL and HTTPS connections failed, using the https://files.pythonhosted.org/ server.

Update it like this:

sudo date -s "Wed Thu  23 11:12:00 GMT+1 2018"
sudo dpkg-reconfigure tzdata

Or directly with e.g. Google’s time:

Ref.: https://superuser.com/a/635024/935136

sudo date -s "$(curl -s --head http://google.com | grep ^Date: | sed 's/Date: //g')"
sudo dpkg-reconfigure tzdata

I recently ran into this problem because of my company’s web content filter that uses its own Certificate Authority so that it can filter SSL traffic. PIP doesn’t seem to be using the system’s CA certificates in my case, producing the error you mention. Downgrading PIP to version 1.2.1 presented its own set of problems later on, so I went back to the original version that came with Python 3.4.

My workaround is quite simple: use easy_install. Either it doesn’t check the certs (like the old PIP version), or it knows to use the system certs because it works every time for me and I can still use PIP to uninstall packages installed with easy_install.

If that doesn’t work and you can get access to a network or computer that doesn’t have the issue, you could always setup your own personal PyPI server: how to create local own pypi repository index without mirror?

I almost did that until I tried using easy_install as a last ditch effort.

You can try to bypass the SSL error by using http instead of https. Of course this is not optimal in terms of security, but if you are in a hurry it should do the trick:

pip install --index-url=http://pypi.python.org/simple/ linkchecker

The answers to use

pip install --trusted-host pypi.python.org <package>

work. But you’ll have to check if there are redirects or caches pip is hitting. On Windows 7 with pip 9.0.1, I had to run

pip install \
  --trusted-host pypi.python.org \
  --trusted-host pypi.org \
  --trusted-host files.pythonhosted.org \
  <package>

You can find these with the verbose flag.

I installed pip 1.2.1 with easy_install and upgraded to latest version of pip (6.0.7 at the time) which is able to install packages in my case.

easy_install pip==1.2.1
pip install --upgrade pip

You have 4 options:

Using a certificate as parameter

$ pip install --cert /path/to/mycertificate.crt linkchecker

Using a certificate in a pip.conf

Create this file:

$HOME/.pip/pip.conf (Linux)

%HOME%\pip\pip.ini (Windows)

and add these lines:

[global]
cert = /path/to/mycertificate.crt

Ignoring certificate and using HTTP

$ pip install --trusted-host pypi.python.org linkchecker

Ignoring certificate and using HTTP in a pip.conf

Create this file:

$HOME/.pip/pip.conf (Linux)

%HOME%\pip\pip.ini (Windows)

and add these lines:

[global]
trusted-host = pypi.python.org

Source

• https://pip.pypa.io/en/latest/user_guide/#configuration

First of all,

    pip install --trusted-host pypi.python.org <package name>

did not work for me. I kept getting the CERTIFICATE_VERIFY_FAILED error. However, I noticed in the error messages that they referenced the ‘pypi.org’ site. So, I used this as the trusted host name instead of pypi.python.org. That almost got me there; the load was still failing with CERTIFICATE_VERIFY_FAILED, but at a later point. Finding the reference to the website that was failing, I included it as a trusted host. What eventually worked for me was:

    pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org <package name>

I’m not sure if this is related, but I had a similar problem which was fixed by copying these files from Anaconda3/Library/bin to Anaconda3/DLLs :

libcrypto-1_1-x64.dll

libssl-1_1-x64.dll

Had the same problem trying pip install ftputil with ActivePython 2.7.8, ActivePython 3.4.1, and “stock” Python 3.4.2 on 64-bit Windows 7 Enterprise. All attempts failed with the same errors as OP.

Worked around the problem for Python 3.4.2 by downgrading to pip 1.2.1: easy_install pip==1.2.1 (see https://stackoverflow.com/a/16370731/234235). Same fix also worked for ActivePython 2.7.8.

The bug, reported in March 2013, is still open: https://github.com/pypa/pip/issues/829.

Nothing on this page worked for me until I used the –verbose option to see that it wanted to get to files.pythonhosted.org rather than pypi.python.org:

pip install --trusted-host files.pythonhosted.org <package_name>

So check the URL that it’s actually failing on via the –verbose option.

I solved this problem by removing my pip and installing the older version of pip: https://pypi.python.org/pypi/pip/1.2.1

You can try this to ignore “https”:

pip install --index-url=http://pypi.python.org/simple/ --trusted-host pypi.python.org  [your package..]

One solution (for Windows) is to create a file called pip.ini on the %AppData%\pip\ folder (create the folder if it doesn’t exist) and insert the following details:

[global]
cert = C:/certs/python_root.pem
proxy = http://my_user@my_company.com:my_password@proxy_ip:proxy_port

…and then we can execute the install instruction:

pip3 install PyQt5

Another option is to install the package using arguments for the proxy and certificate…

$ pip3 install --proxy http://my_user@my_company.com:my_password@proxy_ip:proxy_port \
   --cert C:/certs/python_root.pem PyQt5

To convert the certificate *.cer files to the required *.pem format execute the following instruction:

$ openssl x509 -inform der -in python_root.cer -out python_root.pem

Hope this helps someone!

In my case it was due to SSL certificate being signed by internal CA of my company. Using workarounds like pip --cert did not help, but the following package did:

pip install pip_system_certs

See: https://pypi.org/project/pip-system-certs/

This package patches pip and requests at runtime to use certificates from the default system store (rather than the bundled certs ca).

This will allow pip to verify tls/ssl connections to servers who’s cert is trusted by your system install.

for me this is because previously I’m running script which set proxy (to fiddler), reopening console or reboot fix the problem.

Recently I faced the same issue in python 3.6 with visual studio 2015. After spending 2 days, I got the solution and its working fine for me.

I got below error while try to install numpy using pip or from visual studio Collecting numpy Could not fetch URL https://pypi.python.org/simple/numpy/: There was a problem confirming the ssl certificate: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:748) – skipping Could not find a version that satisfies the requirement numpy (from versions: ) No matching distribution found for numpy

Resolution :

For Windows OS

1. open -> “%appdata%” Create “pip” folder if not exists.
2. In pip folder create “pip.ini” file.
3. Edit file and write
   [global]
   trusted-host = pypi.python.org Save and Close the file. Now install using pip/visual studio it works fine.

In my case, I was running Python in the minimal alpine docker image. It was missing root CA certificates. Fix:

apk update && apk add ca-certificates

Vaulstein answer helped me.

I did not find the pip.ini file anywhere on my pc. So did the following.

1. Went to the the AppData folder. You can get the appdata folder by opening up the command prompt and type echo %AppData%

Or simply type %AppData% in windows explorer.

2. Create a folder called pip inside of that appdata folder.

3. In that pip folder that you just created, create a simple textfile called pip.ini

4. Past the following config settings in that file using a simple editor of your choice.

pip.ini file:

[list]
format=columns

[global]
trusted-host = pypi.python.org pypi.org

You should now be good to go.

I faced a similar issue. The solution that worked for me 1) uninstall python 2.7 2) delete python27 folder 3) reinstall the latest python

For me none of the suggested methods worked – using cert, HTTP, trusted-host.

In my case switching to a different version of the package worked (paho-mqtt 1.3.1 instead of paho-mqtt 1.3.0 in this instance).

Looks like problem was specific to that package version.

You may have this problem if some certificates are missing in your system.eg on opensuse install ca-certificates-mozilla