Port 515LPD Print Service

Port 515 is traditionally used by the Line Printer Daemon (LPD) protocol on Unix/Linux systems to manage print jobs over a network. It enables clients to submit, query, and manage printer queues remotely, facilitating distributed printing in larger network environments..

transport
tcp

single transport

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
7,824

rank 653 of 993 · top 66%

Technical Details

what runs on :515
  • Overview: Port 515 is assigned to the Line Printer Daemon (LPD) protocol, part of the Berkeley printing system, designed primarily for Unix-like environments to enable networked printing. It follows a simple plaintext protocol allowing clients to send print jobs, check queue status, or cancel print jobs remotely.

  • Functionality: Clients connect over TCP port 515 to issue commands to a print server running an LPD service (like lpd, or LPRng). The protocol supports transmitting job control commands, transferring printing data files, and managing queue information. By nature, the communication is unencrypted, relying on trust within local networks.

  • Evolution: While foundational in the early era of networked printing, LPD has seen replacements by more modern protocols such as Internet Printing Protocol (IPP), which includes encryption and advanced management features, but LPD remains prevalent in legacy systems and embedded printer firmware for backward compatibility.

Security Information

exposure of :515

risk score

4/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

network services averages 3.9 across 604 ports — this one sits 0.1 above.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp

every listening transport is another surface to filter at the edge

security overview

  • Common Vulnerabilities:

    • Susceptibility to unauthorized access due to lack of authentication, allowing attackers to insert spurious print jobs or access sensitive documents.
    • Exposure to Denial of Service (DoS) via malformed or oversized print jobs causing resource exhaustion.
    • Potential vector for information disclosure if print job data contains sensitive material sent in plaintext.
    • Use of LPD on Internet-exposed systems can lead to exploitation or as an entry point in multi-stage attacks.
  • Mitigations:

    • Restrict LPD access to trusted internal hosts via firewall rules, blocking inbound port 515 from untrusted networks.
    • Migrate to modern, secure protocols like IPP with SSL/TLS encryption where feasible.
    • Employ network segmentation to isolate print infrastructure.
    • Regularly update printer firmware and server software to patch vulnerabilities.
    • Enable auditing and logging of print activity to detect abuse or anomalies.

the 8 most looked-up other ports in network services — 604 ports carry that label.

risk mix of the 8 listed

  • caution100%

0 of 8 encrypted