2.1 Ports & Protocols: 427 – SLP 2. Networking (220-1001), Comptia A+ (Plus), Comptia A+ (Plus) 220-1001 This entry is part 59 of 230 in the series Comptia A+ (Plus) 220-1001 Series SLP stands for Service Location Protocol. SLP allows computers and other devices to find services without prior configuration. SLP is mostly used on Apple devices (MacOS). SLP uses TCP/UDP Port 427. Author: Previous Article 2.1 Ports & Protocols: 445 – SMB/CIFS Next Article 2.1 Ports & Protocols: 548 – AFP Latest Posts Storage Area Network (SAN) APM and ACPI Acceptable Use Policy