Amazon Web Services (AWS)

Self Hosted only

How to host you pascom phone system server in the Amazon Cloud (AWS)

Recommeded AWS Instance Sizes

< 10 Users < 50 Users < 250 Users < 500 Users < 1000 Users
Instance Type1 t2.small t2.medium t2.large t2.xlarge t2.2xlarge
EBS Volume2 32 GB 64 GB 128 GB 256 GB 512 GB

1) By higher CPU loads, it is advisable to choose the fee-based “t2 unlimited” option. The load depends on entirely on the respective user behaviour. Therefore, our recommendation is to start without the option and monitor the instance using the AWS monitoring tools.

2) In standard use cases, the pascom does not generate a high IO load. As such, the volume type “magnetic” is sufficient.

AWS Instance Setup

pascom has made a Community AMI available at the AWS Frankfurt site:

Select AMI

Continue with the AWS instance setup and make all further settings changes according to our recommendations until you reach step 6 Configure Security Group.

Configure Security Group


You must be able to access the following ports as an Administrator. Under no circumstances share these ports with unrestricted internet access. The simplest option here is to restrict the source IP address to name of your company network. Alternatively, you can use a VPN or a direct AWS connection.

Port Description
TCP 22 SSH Server
TCP 8443 Management Web Interface

Telephony and Instant Messaging

To use the telephony and instant messaging services, open these ports for unrestricted access via the Internet.

Port Description
TCP 80/443 Phone system Web Interface - Important for Let’s Encrypt certificates
TCP 5061 SIP-TLS - secure SIP communication
TCP 5222 pascom Desktop and Mobile client access
UDP 30000 - 35000 SRTP - encrypted Voice Data
UDP 3478 Access for Video-Functionality

Optional Services

Provide the following ports unrestricted access via the Internet only when you actually use the following services.

Port Description
TCP 636 LDAPS for telephone book access via LDAP
TCP 8884 Provisioning of Desktop IP Phones (hardware telephones)
TCP 8885 VPN Tunnel direct to the phone system

Example Configuration

In this example configuration, we used the fixed source IP address of to secure the management Interface:

AWS Security Group

AWS SSH Key Pair

The pascom Server does not require any AWS SSH Key Pairs. Therefore, select Proceed without a key pair and start the instance. Lastly, you can set the passwords via the pascom Server Management.

Start pascom Setup Wizard

Open a browser window and surf to your pascom server’s AWS IP address. Follow the instructions until you can login to the pascom management UI:

pascom Server Management

Domain Name Setup

As valid certificates can only be created using the domain name and not IP addresses, you will now need to setup a domain name for the external AWS IP address.

Should you not have your own, external DNS server available,no-ip offers an easy way to setup domain names.

Activate Let’s Encrypt

The pascom phone system server has the capability to fully and automatically setup a Let’s Encrypt certificate for you. Simply follow these steps:

  • Using an admin account, login to the pascom server Web UI
  • Click
  • Click on the interface used by you
  • Under Interface DNS Name enter the previously setup Domain Name
  • Switch the the Certificate mode to Let's Encrypt
  • Press to apply the configuration

The Interface will now restart and automatically applies the Let’s Encrypt Certificate. Should the interface restart encounter errors, please check your Firewall Settings, in particular Port TCP 443 and your domain name.

Phone System Setup

An additionnal assistant will help you to finish setting up your phone system and add / invite further users. Proceed as follows:

  • Via a browser window, login into the pascom server as an Admin
  • Click on the and then enter a name for your phone system
  • Follow the setup assistant instructions