Firewall Configuration

CirrusPrint listens on http/https network ports for both browser-based administration and client connections, and also an smtp port for incoming mail deliveries.  In addition, it can be configured to listen on ports for network print jobs, generally one for each target printer device.  By default, those ports are either 25,80, 443, or 27082, 27083, and 27085 for browser access and smtp, and 9200-9999 for network print jobs.

Any application that might connect to these ports needs access through the firewall.  The network print ports should only be accessible from machines that you want to print to the CirrusPrint server.  This may be a LAN address range or specific machines on a local network or data center.  Since network print ports receive unencrypted data, you don't want to print through a public network.

If the internal SMTP server will receive emails from public mail systems, then port 25 must be opened on the firewall, as external mail servers will attempt to connect via that port to deliver mail to the server.  If you will be using that server for internal submissions, where you control the SMTP server in sending applications, then you can use a non-standard port like 27085.

Note that in some cases, there may be multiple firewalls involved in connecting to a server.  For example, an Amazon AWS security group configuration may open port 80, but a Windows or Linux firewall on a virtual machine hosted there may also block port 80, so the port would have to be opened on both firewalls.