Requirements

System Requirements

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)	40 GB

These requirements are valid for each Node in a Carbonio Installation and may vary depending on the size on the infrastructure, which includes the number of mailboxes and the services running on each node.

Supported Virtualization Platforms

VMware vSphere 6.x

VMware vSphere 7.x

XenServer

KVM

Virtualbox (testing purposes only)

Software Requirements

Carbonio CE is available for 64-bit CPUs only and can be installed on top of any vanilla Ubuntu 20.04 LTS Server Edition or RHEL 8 installation.

Installation on Other Linux Distributions

While they are not officially supported, Linux distributions compatible with Ubuntu 20.04 (e.g., Debian) and RHEL 8 (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. valid DNS resolution for both the domain (MX and A records) and the FQDN (A record)

   Warning

   If any of these records is not correctly configured, the installation will be temporarily suspended to allow the change of the hostname

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

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

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

See the dedicated box below for details and examples.

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

Additional Requirements

• Acquaintance with the use of CLI is necessary. 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.

• 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.

Configuring DNS resolution

To make sure that the DNS is correctly configured for both A and MX records: to do so, you can use any DNS resolution server, including dnsmasq, systemd-resolved, and bind.

We show as an example, only suitable for demo or testing purposes, how to install and configure dnsmasq for DNS resolution.

Example: Set up of dnsmasq for demo or test environment

Follow these simple steps to set up dnsmasq. These instructions are suitable for a demo or testing environment only.

Warning

On Ubuntu 20.04, installing and running dnsmasq may raise a port conflict over port 53 UDP with the default systemd-resolved service, so make sure to disable the latter before continuing with the next steps.

Ubuntu

# apt install dnsmasq

RHEL

# dnf install dnsmasq

To configure it, add the following lines to file /etc/dnsmasq.conf:

server=1.1.1.1
mx-host=example.com,mail.example.com,50
host-record=example.com,172.16.0.10
host-record=mail.example.com,172.16.0.10

Remember to replace the 172.16.0.10 IP address with the one of your server. Then, make sure that the etc/resolv.conf contains the line:

nameserver 127.0.0.1

This will ensure that the local running dnsmasq is used for DNS resolution. Finally, restart the dnsmasq service

# systemctl restart dnsmasq

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 and Carbonio Mesh must be opened on all nodes, while those in the External Connections only on the node on which the service runs. For example, port 443 should be opened only on the node hosting the Proxy Role.

TCP External Connections

Port	Service
25	Postfix incoming mail
80	unsecured connection to the Carbonio web client
110	external POP3 services
143	external IMAP services
443	secure connection to the Carbonio web client
465	deprecated SMTP authentication relay [1]
587	Port for smtp autenticated relay, requires STARTTLS (or opportunistic SSL/TLS)
993	external IMAP secure access
995	external POP3 secure access
6071	secure access to the Admin Panel

[1]

This port is still used since in some cases it is considered safer than 587. It requires on-connection SSL.

Warning

SMTP, 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

Port	Service
22	SSH access
389	unsecure LDAP connection
636	secure LDAP connection
3310	ClamAV antivirus access
6071	secure access to the Admin Panel
7025	local mail exchange using the LMTP protocol
7026	bind address of the Milter service
7071	Port for SOAP services communication
7072	NGINX discovery and authentication
7073	SASL discovery and authentication
7110	internal POP3 services
7143	internal IMAP services
7171	access Carbonio configuration daemon (zmconfigd)
7306	MySQL access
7993	internal IMAP secure access
7995	internal POP3 secure access
8080	internal HTTP services access
8735	Internal mailbox mailbox communication
8742	internal HTTP services
8743	internal HTTPS services
10024	Amavis Postfix
10025	Amavis OpenDKIM
10026	configuring Amavis policies
10028	Amavis content filter
10029	Postfix archives access
10032	Amavis SpamAssassin
23232	internal Amavis services access
23233	SNMP-responder access
11211	memcached access

Ports Used by Carbonio Mesh

These ports are used by Carbonio Mesh internally.

Port	Protocol	Service
8300	TCP Only	management of incoming requests from other agents
8301	TCP and UDP	management of gossip protocol [3] in the LAN
8600	TCP and UDP	DNS resolutions
8500	TCP Only	clients access to HTTP API
21000-21255	TCP range only	Automatical Sidecar service registrations

[3]

The Gossip protocol is an encrypted communication protocol used by Carbonio Mesh for message broadcasting and membership management.

Ports Used by Carbonio Monitoring

The Carbonio Monitoring component requires the following ports to be accessible by the server. Each port must be opened on the Node on which the corresponding exporter is installed.

Note

If you plan to allow access to Carbonio Monitoring from external networks, make sure that port 9090 TCP on the Carbonio Monitoring server is reachable.

Port	Protocol	Package/Exporter
9115	TCP	carbonio-prometheus-blackbox-exporter
9107	TCP	carbonio-prometheus-consul-exporter
9104	TCP	carbonio-prometheus-mysqld-exporter
9113	TCP	carbonio-prometheus-nginx-exporter
9100	TCP	carbonio-prometheus-node-exporter
9330	TCP	carbonio-prometheus-openldap-exporter
9187	TCP	carbonio-prometheus-postgres-exporter
9256	TCP	carbonio-prometheus-process-exporter