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Windows Agent sent Prolog, with Letsencrypt SSL

The environment:

Debian 9





Hey guys, I have a problem with Letsencrypt certificates. When I requested Letsencrypt cert I only got 2 certificates, and got to be used in Apache ssl config:

SSLCertificateFile /etc/letsencrypt/live/<my domain>/fullchain.pem
SSLCertificateKeyFile /etc/letsencrypt/live/<my domain>/privkey.pem

  • I tried two of them in Agent package as cacert.pem, but the Fullchain dropped this error:

ERROR *** AGENT => Failed to send Prolog <Peer certificate cannot be authenticated with given CA certificates>

  • Privkey.pem have this kind of error:

ERROR *** AGENT => Failed to send Prolog <Problem with the SSL CA cert (path? access rights?)>

I use these command line parameters in Agent:

/S /NOW /SERVER=https://mydomain.com/ocsinventory /SSL=1 /NOSPLASH /TAG="Laptop"

I've read about in google and find a solution which is not clear for me. The link for solution:


I also in the same situation, than "mathew.chen" but the answer which he marked is not work for me or I do something wrong. Please someone explain it to me deeply step by step what should I do, where should I put the certificate which he recommend? Or can anybody confirm that the recommended solution is worked for her/him?

Under the list of certificates which I tried:

in OCS Inventory NG agent for Windows by (320 points)
edited by

5 Answers

+2 votes
Best answer


Follow this procedure and everything will works fine.

1: a2enmod ssl

2: service apache2 restart

3: ln -s /etc/apache2/sites-available/default-ssl.conf /etc/apache2/sites-enabled/default-ssl.conf

4: openssl genrsa -des3 -out privkey.key 2048

5: mv privkey.key privkey-old.key

6: openssl rsa -in privkey-old.key -out privkey.key

enter pass phrase

7: openssl req -new -key privkey.key -out fullchain.csr

Fill in all fields:

  • Country Name (2 letter code)
  • State or Province Name (full name)
  • [Some-State]
  • Locality Name (eg, city)
  • Organization Name (eg, company) [Internet Widgits Pty Ltd]
  • Organizational Unit Name (eg, section)
  • Common Name (e.g. server FQDN or YOUR name)
  • Email Address


Remember to enter the same name in “Common Name” that will be used for connecting by client computers. Otherwise agents will not be able to communicate with server.

8: openssl x509 -req -days 3650 -in fullchain.csr -signkey privkey.key -out fullchain.pem

9: cp fullchain.pem /etc/ssl/certs/

10: cp privkey.key /etc/ssl/private/

11: nano /etc/apache2/sites-enabled/default-ssl.conf

comment your two lines

# SSLCertificateFile /etc/letsencrypt/live/<my domain>/fullchain.pem
# SSLCertificateKeyFile /etc/letsencrypt/live/<my domain>/privkey.pem

and creat theses two lines:

SSLCertificateFile      /etc/ssl/certs/fullchain.pem
SSLCertificateKeyFile /etc/ssl/private/privkey.key
12: service apache2 restart
13: copy the  /etc/ssl/certs/fullchain.pem and rename it in cacert.pem and included it on the OCSpackage.exe and finally deploy it on the PC.
by (740 points)
selected by
0 votes

Thanks for your answer and help.

I am going to mark your post as the best answer, but I am sad, that there is still no chance to use letsencrypt as cacert.pem.

Okay-okay I would use the letsencrypt for the browser say it is a safe website. Without it it is says that it is unsafe, but the administrators would use that website only, so no problem with it.

Thanks again.
by (320 points)
0 votes
I will try with letsencrypt because i also want to use signed certificate.

I tried with the wild card certificate but the agent doens't works properly.

I'll give you feedback if i can do something with letsencrypt
by (740 points)
0 votes
Let’s Encypt will only issue certificates for public domain names that it can verify.

In my case it's not a public webserver. Maybe it's the same for you.

I can't use it.
by (740 points)
0 votes
I agree with you, because we (only us as administrators) will use it it is not necessary to use with a public, accepted certificate.

All in all, thanks for your help. I recommend to the others to make an own certificate than use for example Letsencrypt.
by (320 points)
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