Requirements#

Carbonio CE can be installed in Single-Server or Multi-Server, with the various services and Roles spread across two or more Nodes.

Requirements are divided into groups: System Requirements for a Node, Software Requirements for a Node, RHEL Specific Requirements, and Additional Requirements.

To make requirements easier to understand, we provide software requirements for a Node, which is either the only server used in a Single-Server or each server in a Multi-Server infrastructure.

System Requirements for a Node#

Hardware requirements

CPU

Intel/AMD 64-bit 4 cores min./8+ cores vCPU

RAM

16 GB min., 32+ GB recommended

Disk space (operating system and Carbonio CE)

50 GB

These requirements are valid for each Node in a Carbonio CE Installation and may vary depending on the size of the infrastructure, which includes the services running on each node and the number and size of each mailbox. This means that if for example you plan to assign a 10GB quota to each of your 20 users, you must increase the Disk space requirements accordingly, i.e., to around 250GB total.

Supported Virtualization Platforms

VMware vSphere 6.x

VMware vSphere 7.x

XenServer

KVM

Virtualbox (testing purposes only)

Software Requirements for a Node#

Carbonio CE is available for 64-bit CPUs only and can be installed on top of any of these vanilla distributions:

Support for other distributions will be announced in due course when it becomes available.

Installation on Other Linux Distributions

While they are not officially supported, Linux distributions compatible with Ubuntu (e.g., Debian) and RHEL (e.g., AlmaLinux, Rocky Linux) may be used as base OS for Carbonio CE, provided all dependencies can be satisfied. This may include adding third-party repositories or manually installing software packages.

Moreover, even if Carbonio CE can be installed on an unsupported distribution, it may require some additional effort to have all Carbonio CE Components working, for example to manually edit some configuration file, while some Component may be not working at all. If you face some problems on unsupported distributions or if you successfully installed Carbonio CE on a unsupported distribution and want to share your result, you may want to join the Official Community Forum.

The following requirements must be satisfied before attempting to install Carbonio CE.

  1. The whole Carbonio CE infrastructure must have at least one public IP address. You need to create a DNS A record that resolves to the public IP (e.g., A mail.example.com)

    Hint

    You can check a domain’s A record using the CLI utility host:

    # host -t A example.com
    
  2. To allow the mail server to receive mail, it will be necessary to set up an MX record, which must correspond to the A record (e.g. MX: example.com = mail.example.com )

    Hint

    You can check a domain’s MX record using the CLI utility host:

    # host -t MX example.com
    

    If either of the A or MX records is not correctly configured, the installation will be temporarily suspended to allow the change of the hostname.

  3. Each Node must be able to carry out DNS resolution autonomously and be able to resolve all other Nodes

  4. For improved security of sending emails, you should also define TXT records for SPF, DKIM and DMARC

  5. Python 3, latest version available on the chosen Operating System

  6. Perl, latest version available on the chosen Operating System

  7. IPv6 must be disabled. Make also sure that the /etc/hosts does not contain any IPv6 entries.

RHEL Specific Requirements#

Note

If you plan to install Carbonio CE automatically on a Single-Server using the downloadable script (see Section Automatic Script-based Installation), these requirements are checked and automatically enabled if missing.

You need to satisfy these requirements, depending on the RHEL version you want to install:

RHEL 8#

Repositories

If you plan to install Carbonio CE on RHEL 8, you need an active subscription to the following repositories, i.e., you must be able to fetch packages from them

  • BaseOS and the other main repositories:

    # subscription-manager repos --enable=rhel-8-for-x86_64-baseos-rpms
    
  • Appstream:

    # subscription-manager repos --enable=rhel-8-for-x86_64-appstream-rpms
    
  • CodeReady:

    # subscription-manager repos --enable=codeready-builder-for-rhel-8-x86_64-rpms
    
  • EPEL:

    # dnf -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
    
SELinux

SELinux Must be set to disabled or permissive in file /etc/selinux/config. You can check the current profile using the command

# sestatus

RHEL 9 BETA#

Repositories

If you plan to install Carbonio CE on RHEL 9, you need an active subscription to the following repositories, i.e., you must be able to fetch packages from them

  • BaseOS and the other main repositories:

    # subscription-manager repos --enable=rhel-9-for-x86_64-baseos-rpms
    
  • Appstream:

    # subscription-manager repos --enable=rhel-9-for-x86_64-appstream-rpms
    
  • CodeReady:

    # subscription-manager repos --enable=codeready-builder-for-rhel-9-x86_64-rpms
    
  • EPEL:

    # dnf -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm
    
SELinux

SELinux Must be set to disabled or permissive in file /etc/selinux/config. You can check the current profile using the command

# sestatus
New systemd units to replace zmcontrol

By installing Carbonio CE on RHEL 9 you will no longer be able to manage Carbonio services with the legacy zmcontrol start <service>, zmcontrol restart <service>, and zmcontrol stop <service> commands. Interaction with services should be done exclusively through systemd commands.

Note

The zmcontrol -v command, used to retrieve Carbonio CE’s configuration, will continue working as usual.

To get the list of all Carbonio services, use command

# systemctl list-unit-files

Example

You can check the status of the Carbonio Tasks service with:

# systemctl status carbonio-tasks.service

To manage its start, stop, and restart, replace status in the above command with: start, stop, and restart respectively.

It will also not possible to use zmcontrol start | stop | restart as a convenience to restart all Carbonio services at once. This command will be replaced by Role-specific systemd commands, to be executed on the Node on which they are installed.

# systemctl start/stop/restart carbonio-directory-server.target
# systemctl start/stop/restart carbonio-appserver.target
# systemctl start/stop/restart carbonio-mta.target
# systemctl start/stop/restart carbonio-proxy.target

Additional Requirements#

When you do not use the script-based installation, i.e., Single-Server manual installation or Multi-Server installation.

  • All carbonio commands must be executed as the zextras user (these commands will feature a zextras$ prompt), while all other commands must be issued as the root user, unless stated otherwise.

    Note

    The zextras user is created during the Carbonio CE installation process, it is not necessary to create it beforehand.

  • Commands or groups of commands may be different between Ubuntu and RHEL 8. This is shown by blue tabs: click on the tab of your choice to find the correct command.

  • When no such tabs are given, the commands to run are the same on Ubuntu and RHEL 8.

Firewall Ports#

For Carbonio CE to operate properly, it is necessary to allow network communication on specific ports. On a Single-Server installation, only ports in the External Connections must be opened, because all the remaining traffic does not leave the server.

In Multi-Server installation, ports listed in the Internal Connections must be opened on all nodes, while those in the External Connections only on the node on which the corresponding Role is installed. For example, port 443 should be opened only on the node hosting the Proxy Role.

Furthermore, ports in Internal and External connections are grouped according to the Role that require them, so all ports listed in a table must be opened only on the Node on which the Role is installed.

TCP External Connections#

MTA Role

Port

Protocol

Service

25

TCP

Postfix incoming mail

465

TCP

Message Submission over TLS protocol

587

TCP

Port for SMTP autenthicated relay, requires STARTTLS (or opportunistic SSL/TLS)

Warning

These ports should be exposed only if really needed, and preferably only accessible from a VPN tunnel, if possible, to reduce the attack surface.

Proxy Role

Port

Service

80

TCP

unsecured connection to the Carbonio web client

110

TCP

external POP3 services

143

TCP

external IMAP services

443

TCP

secure connection to the Carbonio web client

993

TCP

external IMAP secure access

995

TCP

external POP3 secure access

6071

TCP

secure access to the Admin Panel

Warning

The IMAP, POP3, and 6071 ports should be exposed only if really needed, and preferably only accessible from a VPN tunnel, if possible, to reduce the attack surface.

TCP Internal Connections#

Every Node

Port

Service

22

TCP

SSH access

8301

TCP and UDP

management of Gossip protocol [2] in the LAN

9100

TCP

Carbonio Monitoring Node exporter

9256

TCP

Carbonio Monitoring Process exporter

Postgres Role

Port

Protocol

Service

5432

TCP

Postgres access

9187

TCP

Postgres data export to Carbonio Monitoring

Directory Server Role

Port

Protocol

Service

389

TCP

unsecure LDAP connection

636

TCP

secure LDAP connection

9330

TCP

LDAP data export to Carbonio Monitoring

MTA Role

Port

Protocol

Service

25

TCP

Postfix incoming mail

465

TCP

Message Submission over TLS protocol

587

TCP

Port for SMTP autenthicated relay, requires STARTTLS (or opportunistic SSL/TLS)

7026

TCP

bind address of the Milter service

AppServer Role

Port

Protocol

Service

7025

TCP

local mail exchange using the LMTP protocol

7071

TCP

Port for SOAP services communication

7072

TCP

NGINX discovery and authentication

7073

TCP

SASL discovery and authentication

7110

TCP

internal POP3 services

7143

TCP

internal IMAP services

7993

TCP

internal IMAP secure access

7995

TCP

internal POP3 secure access

8080

TCP

internal HTTP services access

8443

TCP

internal HTTPS services

8735

TCP

Internal mailbox mailbox communication

8742

TCP

internal HTTP services, advanced module

8743

TCP

internal HTTPS services, advanced module

Carbonio VideoServer Role

Port

Protocol

Service

8188

TCP

Internal connection

8090

TCP

Servlet communication

Proxy Role

Port

Protocol

Service

9113

TCP

nginx data export to Carbonio Monitoring

11211

TCP

memcached access

Carbonio Mesh Role

Port

Protocol

Service

8300

TCP

management of incoming requests from other agents

8302

TCP and UDP

management of Gossip protocol [4] in the WAN

9107

TCP

Carbonio Mesh data export to Carbonio Monitoring

21000-21255

TCP

range for registrations ports for sidecar services (automatically assigned)