Creating a single SSL certificate bundle from CA root and intermediate certificates

When you purchase an SSL certificate for a domain, e.g. to secure HTTPS usage with your web server, your certificate download may provide you several files like this: : this is your domain certificate

Files that look this are the root and intermediate certificates:



Depending how your SSL vendor supplies these files, the second two files may be provided already bundled in one file or two separate files.

To combine them together into one bundle file, use cat to concat the files:

cat yourdomain_com.crt USERTrustRSAAddTrustCA.crt AddTrustExternalCARoot.crt >

Open the file and check that each start and end comment for each cert are on their own line and not on the same line (see here).

http-server with self-signed certs and enabling support in Chrome

To test loading a site locally with http-server you need to generate self-signed certs:

openssl req -newkey rsa:2048 -new -nodes -x509 -days 365 -keyout key.pem -out cert.pem

Now start up http-server using the new cert:

http-server -S -C cert.pem -o .

If you attempt to browse https://localhost:8080 though, Chrome will block self-signed certs by default. To allow self-signed certs, enter in your Chrome address bar:


And then enable the highlighted setting:

Let’s Encrypt certificate expired on older Macs

I have a number of older machines that I use on a regular basis, so I’m no stranger to the struggles of not being able to browse current websites on older machines with older browsers and the typical SSL/TLS support issues that you run into. I was surprised to see this error this week on my 2008 Mac Pro running Mac OS X 10.11 El Capitan and a latest version of Chrome:

Looking at the certificate for any site not loading it looks like the certificate has expired:

I’m not seeing this on my other later/current machines though, so clearly something on these older machines is no longer getting updates. Browsing around a few other sites and seeing the same issue on many sites so it was not just limited to a single site, so I realized something else was going on. Some Googling found this article:

Following the steps to download the updated certificate from LetsEncrypt and install it into Keychain did the job.

SSL certs upgraded, Docker images upgraded, ready to go!

I had to renew my SSL certs for this site, so while doing so I upgraded and addressed a few other issues.

First, apparently when I deployed the SSL certs last time I missed out some of the root certs in the chain. The vendor I used gives you each of the root certs individually and you need to manually concatenate them together yourself. More in another post on the steps I too to do this.

Since certs are part of my nginx Docker image, I rebuilt my image upgrading everything to latest versions. Since it was a also a couple of years since I last did this, I also had to go back through my posts here to work out the steps I took to deploy last time. I’ll post another update on the steps I took for this also later.