HP ProLiant Network Adapters — Complete Buying Guide (FLR, FLB, FlexFabric)

Published April 18, 2026 · 12 min read · By Pro Disk Network Team

Everything you need to know about HP server network adapters — the difference between FLR and FLB, how to choose the right HP 331FLR, 530FLR, 544FLR, or FlexFabric adapter, and compatible part numbers for every ProLiant generation.

Topics: HP network adapter, HP 331FLR, HP FlexFabric, HP 530FLR, ProLiant NIC, HP FLR

Why HP ProLiant Network Adapters Matter

Choosing the wrong HP network adapter for your ProLiant server is an expensive mistake. Plug in the wrong form factor — an FLB into a rack server that needs FLR, or a standard PCIe card into a FlexibleLOM slot — and you have a paperweight.

This guide covers every HP ProLiant network adapter form factor, the compatible servers for each, and the specific part numbers you should be ordering for common upgrade scenarios in 2026.

HP Network Adapter Form Factors Explained

HP ProLiant servers use two proprietary adapter interfaces in addition to standard PCIe slots:

FLR — FlexibleLOM Riser (Rack Servers)

FLR adapters are designed for HP ProLiant rack servers (DL series). They install in the FlexibleLOM slot on the system board — a dedicated connector that provides PCIe bandwidth directly from the CPU without consuming a standard PCIe slot.

Key characteristics:

• Only fits DL (rack) series ProLiant servers
• Single adapter serves as the primary NIC — you do not need a PCIe riser card
• FLR adapters are labeled with "-FLR" suffix in HP part numbers (e.g., 331FLR, 530FLR)

Which servers use FLR: DL160, DL180, DL360, DL380, DL385, DL560, DL580, DL80, DL120

FLB — FlexibleLOM Blade (Blade Servers)

FLB adapters are designed for HP BladeSystem blade servers (BL series). They install in the FlexibleLOM connector on the blade module.

Key characteristics:

• Only fits BL (blade) series ProLiant servers
• FLB adapters labeled with "-FLB" suffix (e.g., 530FLB, 554FLB)
• Cannot be installed in rack servers — connector is different

Which servers use FLB: BL420c, BL460c, BL465c, BL660c (within HP c3000/c7000 blade chassis)

FlexFabric Technology

HP FlexFabric is an adapter technology (not a form factor) available in both FLR and FLB variants. FlexFabric adapters support partitioning — a single physical port can be split into multiple virtual ports (up to 4 per physical port), each with:

• Independently configured bandwidth (Ethernet, FCoE, iSCSI)
• Guaranteed minimum and maximum bandwidth per partition
• Support for mixing Ethernet and storage traffic on a single physical connection

FlexFabric is HP's answer to converged network adapters (CNAs), combining LAN and SAN traffic without separate HBAs.

HP 331FLR — The Standard 1GbE FLR Adapter

The HP 331FLR (part number 629135-B21) provides:

• 4x 1GbE ports (RJ-45 copper)
• Broadcom BCM5719 chipset
• PCI-Express x4 FlexibleLOM interface
• Compatible with Gen8, Gen9, and some Gen10 servers

HP 331FLR Part Numbers

Buy HP 331FLR adapters

331FLR Compatible Servers

Note: For ProLiant Gen10 servers (DL360/DL380/DL385/DL560/DL580 Gen10), HPE lists the 629135-B22 revision of the 331FLR as supported.

HP 530FLR — 2-Port 10GbE FLR Adapter

The HP 530FLR-SFP+ provides dual-port 10GbE connectivity via SFP+ for rack servers.

Buy HP 530FLR adapters

530FLR Compatible Servers

DL160 Gen8, DL360p Gen8, DL380p Gen8, DL385p Gen8, DL560 Gen8

HP 544FLR — Dual-Port 10GbE/InfiniBand FLR

The HP 544FLR-QSFP is a high-performance dual-port adapter supporting both 10/40GbE and FDR InfiniBand on the same physical hardware. Used in HPC and high-density virtualization environments.

• Connectivity: 2x QSFP (10/40GbE or FDR InfiniBand)
• Chipset: Mellanox ConnectX-3
• Use cases: HPC clusters, large-scale virtualization, converged Ethernet + InfiniBand

Buy HP 544FLR adapters

HP 561FLR-T — 2-Port 10GbE Copper FLR

The HP 561FLR-T provides dual-port 10GBase-T (RJ-45 copper) at 10GbE speeds, eliminating the need for SFP+ transceivers and fiber cabling. Popular for ToR switch connections where 10GBase-T is used.

Compatible with Gen8 and Gen9 DL series servers.

Buy HP 561FLR-T adapters

HP 530FLB — 2-Port 10GbE Blade Adapter (FLB)

For BL series blade servers, the 530FLB provides dual-port 10GbE in the mezzanine form factor.

Buy HP 530FLB adapters

HP FlexFabric Adapters — Converged Networking

For environments that need Ethernet and storage (FCoE/iSCSI) over the same physical links:

Browse all HP FlexFabric adapters

Gen10 Adapters — 366FLR Series

ProLiant Gen10 servers (DL360/DL380/DL560 Gen10) support the 366FLR:

Important: For Gen10, use the 366FLR or the 629135-B22 revision of the 331FLR.

Quick Selection Guide

Where to Buy HP ProLiant Network Adapters

Pro Disk Network stocks HP network adapters for ProLiant servers from Gen6 through Gen10.

• HP 331FLR — 1GbE 4-Port FLR Adapters
• HP 530FLR — 10GbE SFP+ FLR Adapters
• HP 544FLR — 10GbE/InfiniBand FLR Adapters
• HP 561FLR-T — 10GbE Copper FLR Adapters
• HP FlexFabric 10GbE Adapters
• HP 530FLB — 10GbE Blade Adapters
• All HP Network Adapters

For bulk pricing or compatibility questions, email sales@prodisknetwork.com.