RFC 1918 Private IP Ranges
The three private IPv4 address blocks and their common uses.
RFC 1918 reserves three blocks of IPv4 address space for private internets: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Addresses in these ranges are not routable on the public internet and can be used freely inside any organization.
Choosing the right block depends on scale. The 10.0.0.0/8 range offers over 16 million addresses and is the standard choice for enterprise networks; 172.16.0.0/12 is common in mid-size networks and is the default for AWS VPCs; 192.168.0.0/16 is the familiar choice for SMB, branch, and home networks.
| CIDR | Range Start | Range End | Hosts | Common Use |
|---|---|---|---|---|
| 10.0.0.0/8 | 10.0.0.0 | 10.255.255.255 | 16,777,216 | Large enterprise networks |
| 172.16.0.0/12 | 172.16.0.0 | 172.31.255.255 | 1,048,576 | Mid-size networks, AWS VPC default |
| 192.168.0.0/16 | 192.168.0.0 | 192.168.255.255 | 65,536 | SMB, home networks, branch offices |
Read More
Guides that go deeper on the same topic.
IPv6 Address Management: A Practical Guide to Subnetting, Planning, and Dual-Stack Migration
A practical guide to IPv6 address management: /64 subnetting, /48 site planning, ULA, dual stack migration, and pitfalls that catch teams moving from IPv4.
Subnetting Guide for Network Engineers
A practical subnetting guide for network engineers covering CIDR notation, subnet plan design, VLAN and VRF mapping, common pitfalls, and tools for keeping your IP space organized at scale.
IP Address Management Best Practices in 2026
IP address management has evolved beyond simple spreadsheets. Learn the key practices, tooling decisions, and operational patterns that define modern IPAM in 2026.
More Reference
Explore the other reference in the toolkit.
Common TCP & UDP Ports
Reference list of common TCP and UDP ports: SSH, DNS, HTTP, HTTPS, SMTP, NTP, DHCP, SNMP, RDP, and more, with protocols and descriptions.
Fiber Connector Types
Reference guide to fiber optic connector types: LC, SC, ST, FC, MPO/MTP, and E2000 with polish, return loss, and typical use.
Ethernet Standards (IEEE 802.3)
Reference table of IEEE 802.3 Ethernet standards: 1000BASE-T, 10GBASE-T, 10GBASE-SR/LR, 25G, 40G, 100G, and 400G with media and distances.
RFC References for Network Engineers
Quick reference list of the essential networking RFCs every infrastructure engineer should know, from RFC 1918 to BGP, DHCP, DNS, and NTP.
Reserved & Special-Use IP Addresses
Reference table of special-use IPv4 ranges: loopback, link-local (APIPA), CGNAT, TEST-NET documentation ranges, multicast, and broadcast.
TIA-606 Cable Color Codes & Labeling Standard
TIA-606 labeling standard and cable color codes for structured cabling: blue for horizontal cabling, orange for demarcation, purple for common equipment, identifier formats, and admin classes.
Transceiver Form Factors
Reference table of optical transceiver form factors: SFP, SFP+, SFP28, QSFP+, QSFP28, QSFP-DD, CFP2, XFP, and CXP with speeds and distances.
WiFi Standards (IEEE 802.11)
Reference table of WiFi standards and generations: 802.11b through 802.11be (Wi-Fi 1 to Wi-Fi 7) with maximum speeds, frequencies, and release years.
Power Connectors & Receptacles
Reference table of data center power connectors: NEMA 5-15P, L6-30P, IEC C13/C14, C19/C20, IEC 60309, Schuko, and BS 1363 with amp and voltage ratings.
Device Naming Conventions
Standard network device naming convention: use a <site>-<role>-<number> pattern. See examples for switches, firewalls, servers, and stack members.
Interface & Port Naming
How to standardize network interface names across vendors: Cisco IOS, Juniper Junos, and NX-OS/AOS-CX conventions with examples.
VLAN & Subnet Naming
Best practices for VLAN naming: descriptive names like SRV-PROD and GUEST-WIFI paired with documented VLAN IDs and subnets.
VLAN ID Ranges & Reserved IDs
Reference table of VLAN ID ranges: the standard range 2-1001, the extended range 1006-4094, reserved IDs (0, 1002-1005, 4095), and the default VLAN 1.