How to install certificate from an SSL Certificate Provider to PBX

In case you've decided to use specific SSL certificate or PBX has no access to Wildix certificate-updater service.

Created: February 2020

Updated: August 2020


Important: in WMS 5.0X Custom certificates are accepted only with signature algorithm not lower than SHA256.

Intro: What is SSL and an SSL Certificate

Secured Socket Layer (SSL) is the technology that ensures that data between two machines (in our case – a browser/ phone and PBX) is transmitted securely in an encrypted connection (HTTPS).

An SSL Certificate is a digital certificate that confirms the identity of a website. It is usually represented as a pair of small text files with encrypted data (Certificate *.crt and Private Key *.key).

To implement SSL on your PBX in the absence of access to Wildix certificate-updater service, you need to:

  • submit a CSR (Certificate Signing Request)  to an SSL Certificate Provider (Certification Authority) and get an SSL Certificate


  • create /wiki/spaces/DOC/pages/30283909 by you own. These certificates are easy to make and they are free. However, they do not provide all of the security properties that certificates signed by a CA aim to provide.

Then you need to import certificate and private key to PBX.

Step-by-step guide

Step 1. 

You can rather request a certificate from a Certification Authority or generate a self-signed certificate.

Get a certificate from a Certification Authority 

  1. Select one of Certificate Providers that suit your requirements. For instance,, Namecheap, TheSSLStore, GoDaddy, GlobalSign, DigiCert, Thawte, GeoTrust, Entrust, Network Solutions, etc.
  2. Create a CSR (Certificate Signing Request) either using a Linux shell (PBX shell preferred) or Certificate Provider tools:

    Linux shell command to create CSR
    openssl req -new -newkey rsa:2048 -nodes -keyout server.key -out server.csr

    CSR configuration requires the details as follows below:

    • Common Name (the domain name of PBX). It is highly recommended to use sub-domain wildcard ( *.<yourdomain>.<com> )
    • Country (two-letter code)
    • State (or province)
    • Locality (or city)
    • Organization
    • Organizational Unit (Department)
    • E-mail address

  3. Keep resulting key and csr files. Its content should include encrypted data and headers :


    ...some data...



    -----BEGIN PRIVATE KEY-----

    ....some data...

    -----END PRIVATE KEY-----

  4. Order a certificate from one of Certificate Providers and provide them the CSR file
  5. Validate domain ownership with CA using one of three validation types: Domain Validated (DV), Organization Validated (OV), Extended Validation (EV) 

    Please note that some sub-types require internet connection.

Generate self-signed certificate 

Generate certificate on LINUX system using the command:

openssl genrsa -des3 -out server.key 2048
openssl rsa -in server.key -out server.key
openssl req -sha256 -new -key server.key -out server.csr -subj “/C=IT/ST=TN/L=My City/O=My Company/”
openssl x509 -req -sha256 -days 3650 -in server.csr -signkey server.key -out server.crt

Use your country instead of IT (Italy) and your region instead of TN (Trento) in the string “/C=IT/ST=TN/L=My City/O=My Company/”


server.crt server.csr server.key

Step 2. Configure internal DNS

Configure internal DNS. PBX domain name should correspond IP of PBX.

Step 3. Import the certificate

To import the certificate:

  1. Login PBX web interface with administrative account
  2. Go to WMS Settings -> PBX -> SIP-RTP
  3. Upload certificate files: Certificate *.crt and Private Key *.key
  4. Click Save