Sign Specifications and Network Configuration
Signs run an LTS version of the Ubuntu operating system. By default, the sign’s network settings are set through DHCP, although a static network configuration is available by request.
Primary communication is performed over port 443 (HTTPS), and is initiated by the sign. By default, this outbound communication occurs every 60 seconds. For networks that restrict access through firewalls or other means, it’s recommended to whitelist all subdomains of signcommand.com (
*.signcommand.com), as well as the Amazon AWS S3 service (
*.s3.amazonaws.com). The specific domains currently in use are:
Signs use the Network Time Protocol (NTP) to keep the internal clock synchronized to an official time source. By default, this source is set to
time.google.com and uses
UDP port 123. This port and domain must be unrestricted on both your network and through your Internet Service Provider for synchronization to work correctly. If you use an internal NTP server, contact support to request a change to the NTP source.
Remote Diagnostics and Administration
In-depth troubleshooting and issue resolution may require command line access to the sign. In this instance, an SSH connection is established to the sign through reverse SSH port forwarding. This access is disabled by default and can be permanently disabled by request. The connection can only be initiated from our Technical Support network.
Signs on the SignCommand network do not require access to an organization’s internal network or direct communication with the machine accessing the client application. You may choose to isolate the sign from the rest of the network, or use another method of communication to the internet entirely.
Control of the sign is achieved through a web browser over a secure connection to the SignCommand servers. For more information, see our Requirements page. For client use on the network, access to the following URLs is required: