More detailsNeighboring subnets, expanded address, reverse DNS, and hextet breakdown
Neighboring /118 subnets
- Expanded address
- Compressed address
- Network (expanded)
- Last address (expanded)
- Prefix mask
- Total addresses (exact)
- Reverse DNS (PTR)
- Host bits / network bits
Hextet breakdown
20010db8abcd00120000000000000001
NetworkSplit groupHost
Quick facts for IPv6 /118
- Prefix mask: ffff:ffff:ffff:ffff:ffff:ffff:ffff:fc00
- Total addresses: 2¹⁰
- Approx. count: 1,024
- /64 subnets: —
IPv6 /118 reference guideBit split, overview, key facts, sizing tables, design notes, standards, and FAQ
Network / host bit split
netnetnetnetnetnetnetmix
Network bits (118)Split hextetHost bits (10)
- Network bits
- 118
- Host bits
- 10
- Prefix mask
- ffff:ffff:ffff:ffff:ffff:ffff:ffff:fc00
- Total addresses
- 2¹⁰
- Approx. count
- 1,024
- /64 subnets
- —
- Addresses formula
- 2^10
- /64 relationship
- smaller than a /64
Overview
A /118 contains 2¹⁰ addresses (1,024), suitable for small VLANs, management subnets, or lab scenarios. Standard production LANs should still use /64; this size is for deliberate constraints.
Common use cases
- Small management VLANs
- Test and staging environments
- Subnetting practice for certification exams
Key facts
- A /118 fixes 118 network bits and leaves 10 host bits — 2¹⁰ total addresses.
- In network design terms, /118 is typically a constrained management or lab segment.
- Written out, /118 holds exactly 1,024 addresses.
- A /118 is 1/2⁵⁴ of a standard /64 LAN subnet.
Design guidance
A /118 can work for small management VLANs, out-of-band networks, or certification lab exercises where you deliberately cap the host count. For router interconnects, prefer /127 (RFC 6164) over /118. For ordinary LANs, stay with /64 regardless of how small the segment feels.
Practical example
In a lab, 2001:db8:abcd:0012::1/118 might number a small segment with 1,024 addresses. In production, you would normally expand this to a full /64 unless you have a documented exception.
Prefix sizing reference
Frequently asked questions
Common questions about IPv6 /118 blocks, prefix sizes, and use cases.