SSL “unable to get local issuer certificate” : “full chain” vs “root”

certificate-authoritycurllets-encryptsslssl-certificate

Summary

In summary I have some certificate related files and some certificate related instructions but I'm not sure which files are which !

Background

I've just installed a certificate from Lets Encrypt by using acme.sh

The output from that process looks like this :

[Sat Aug 18 02:50:24 UTC 2018] Your cert is in  /home/ubuntu/.acme.sh/www.foobar.xyz/www.foobar.xyz.cer
[Sat Aug 18 02:50:24 UTC 2018] Your cert key is in  /home/ubuntu/.acme.sh/www.foobar.xyz/www.foobar.xyz.key
[Sat Aug 18 02:50:24 UTC 2018] The intermediate CA cert is in  /home/ubuntu/.acme.sh/www.foobar.xyz/ca.cer
[Sat Aug 18 02:50:24 UTC 2018] And the full chain certs is there:  /home/ubuntu/.acme.sh/www.foobar.xyz/fullchain.cer

So after configuring Nginx this is all works when requests are made to https://www.foobar.xyz through a conventional browser.

Problem

But when I make the same request via Curl I get :

curl: (60) SSL certificate problem: unable to get local issuer certificate

So it seems there are two ways to fix this.

  • tell Curl to ignore the issue or provide curl with a client side list of certificating authorities.
  • alter the certificate on the server

Question

I want the second option, the change on the server, and this page gives instructions on how to do it specifically …

2) If you received the intermediate certificates in one bundle file or
downloaded the certificate files in your account with us, you can use
this command:

cat example_com.crt bundle.crt >> ssl-bundle.crt

Place the concatenated file into the directory with SSL certificates
on your Nginx server.

The problem I have is that I'm not sure which of the files produced by running acme.sh correspond to the example_com.crt and the bundle.crt ?

I think bundle.crt corresponds to www.foobar.xyz.cer ?

But I'm not sure what example_com.crt corresponds to ?

Best Answer

The bundle is fullchain.cer. It contains ca.cer and www.foobar.xyz.cer.