How to generate a CSR code on Zimbra?

Zimbra is an email server that allows the generation of CSR through the web interface and the command line.

To generate a  CSR (certificate signing request) from Zimbra Administration Console please follow the steps below:

1. Go to Zimbra administration panel
2. Click on Configure from the left menu
3. Then click on Certificates and choose the Install Certificate option
4. Choose the email server and then click Next
5. Choose Generate the CSR to begin the CSR issuance process
   
6. Fill in the required information then click Next
7. Download the generated CSR file

CSR generation via Zimbra Certificate Manager (command line interface)

In order to manage the SSL certificates please use the zmcertmgr tool.

sudo su
su zimbra

Run the below command to generate the CSR for a single domain SSL certificate:

/opt/zimbra/bin/zmcertmgr createcsr comm -new -subject "/C=UK/ST=UK/L=London/O=HostX/OU=NA/CN=server.yourdomain.com" -noDefaultSubjectAltName

Replace the above values with the ones that correpond to your organization.

Alternatively, if you want to generate a CSR for multiple domains, run the below command. Again, don't forget to replace the values below with the ones that correspond to your organization.

/opt/zimbra/bin/zmcertmgr createcsr comm -new -subject "/C=UK/ST=UK/L=London/O=HostX/OU=NA/CN=server.yourdomain.com" -subjectAltNames "alternative1.domain.com,alternative2.domain.com"

The newly created CSR will be available in the following location:

/opt/zimbra/ssl/zimbra/commercial/commercial.csr