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Port 67BOOTP/DHCP Server

Port 67 is primarily used by the Bootstrap Protocol (BOOTP) and the Dynamic Host Configuration Protocol (DHCP) servers to provide IP address assignment and configuration information to network clients. This port facilitates automated network management by enabling servers to dynamically allocate IP addresses, reducing manual configuration overhead..

inNetwork ServicesSystem
transport
udp

single transport

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
7,313

rank 705 of 993 · top 71%

Technical Details

what runs on :67

Port 67, a well-known UDP port, serves as the listening port for the server-side of both BOOTP and DHCP protocols. BOOTP was the original protocol designed to enable diskless workstations to discover their IP address, gateway, and boot file location by querying a server during the boot process. It was largely static in allocation but automated the initial IP distribution.

DHCP was introduced as an enhancement to BOOTP, bringing dynamic allocation capabilities. DHCP servers monitor port 67 for DHCPDISCOVER messages from clients attempting to join the network. The server responds with DHCPOFFER, with further exchanges including DHCPREQUEST and DHCPACK, occurring primarily over port 67. This handshake facilitates dynamic assignment, leasing, renewal, and release of IP addresses and configuration parameters, greatly simplifying network administration.

Operationally, DHCP relies on broadcast requests since clients may not yet have an IP address. DHCP servers use port 67 to listen for requests from clients on port 68. This protocol also supports failover architectures for redundancy and can integrate with directory services or DNS updates for seamless network configuration and management.

Security Information

exposure of :67

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

udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Common Vulnerabilities:

  • DHCP starvation attacks, where an attacker exhausts the DHCP address pool by continuously requesting new leases.
  • Rogue DHCP servers that provide incorrect network information to clients, facilitating man-in-the-middle (MitM), traffic interception, or network disruption.
  • DHCP spoofing, supplying malicious IP configuration such as incorrect gateway or DNS servers.

Common Mitigations:

  • Implementing DHCP snooping on network switches to limit DHCP responses to trusted ports, preventing rogue servers.
  • Employing access controls and authentication where possible to limit who can connect and request addresses.
  • Monitoring DHCP logs actively for unusual lease activity or suspicious DHCP server responses.
  • Using static IP assignments or IP source filtering in critical environments to reduce reliance on DHCP.
  • Segmenting network traffic with VLANs to isolate sensitive hosts from general client DHCP broadcasts.

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all 604 in network services →

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

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risk mix of the 8 listed

  • caution100%

0 of 8 encrypted