Firewalls

This help document describes the ports that CUPS uses so that firewall administrators can allow traffic used for printing.

Ports Used for Printer Sharing

Table 1 lists the ports that are used for IPP printer sharing via CUPS.

Table 1: Ports Used for IPP Printer Sharing
(Destination) Port TCP/UDP Direction Description
53 (DNS) TCP/UDP OUT Domain Name System lookups and service registrations.
631 (IPP/IPPS) TCP IN Internet Printing Protocol requests and responses (print jobs, status monitoring, etc.)
5353 (mDNS) UDP IN+OUT Multicast DNS lookups and service registrations.

Table 2 lists the ports that are used for SMB (Windows) printer sharing, typically via the Samba software.

Table 2: Ports Used for SMB Printer Sharing
(Destination) Port(s) TCP/UDP Direction Description
137 (WINS) UDP IN+OUT Windows Internet Naming Service (name lookup for SMB printing).
139 (SMB) TCP IN Windows SMB printing.
445 (SMBDS) TCP IN+OUT Windows SMB Domain Server (authenticated SMB printing).

Ports Used for Network Printers

Table 3 lists the ports for outgoing network traffic that are used for network printers.

Notes:

  1. DNS and mDNS are used for all printing protocols except SMB.
  2. SNMP is used to provide status and supply level information for AppSocket and LPD printers.
Table 3: Outgoing Ports Used for Network Printers
(Destination) Port(s) TCP/UDP Description
53 (DNS) TCP/UDP Domain Name System lookups.
137 (WINS) UDP Windows Internet Naming Service (name lookup for SMB printing).
139 (SMB) TCP Windows SMB printing.
161 (SNMP) UDP SNMP browsing (broadcast) and status monitoring (directed to printer IP address).
443 (IPPS) TCP Internet Printing Protocol requests and responses (print jobs, status monitoring, etc.)
445 (SMBDS) TCP Windows SMB Domain Server (authenticated SMB printing).
515 (LPD) TCP Line Printer Daemon (LPD/lpr) print job submission and status monitoring.
631 (IPP/IPPS) TCP Internet Printing Protocol requests and responses (print jobs, status monitoring, etc.)
5353 (mDNS) UDP Multicast DNS lookups.
9100-9102 TCP Raw print data stream (AppSocket/JetDirect).