254 addresses sounds like a lifetime supply until phones, cameras and printers move in. This page explains the moment an office truly outgrows /24, the honest alternative of separating networks, and how to step up to /23 without a Monday-morning outage.
'New phone will not join the Wi-Fi, old laptop works fine' — address exhaustion announces itself exactly this quietly. By the time it is obvious, the office is already over the line. Here is how to recognise the moment, judge the options honestly, and make the /23 move in the right order.
☝️ A /23 joins two neighbouring /24 streets into one. Note the network address changes too — the street must start on an even boundary, 192.168.0.0.
A /24 gives 254 usable addresses, which sounds like plenty — until you count honestly. Staff PCs and laptops, phones on Wi-Fi (often two devices per person), printers, CCTV cameras and DVR, attendance machines, smart TVs, the server, spare switch ports already patched. Offices rarely notice the count passing 200, because nothing warns you politely.
The first symptom is strange: new devices randomly fail to get an address while old ones work. A phone joins in the morning and sits on 169.254; by evening, after some leases expire, it works. That is the DHCP pool hitting the ceiling of the street.
Before enlarging, check whether the crowd is real. Many offices solve the pressure by separating instead of expanding: cameras on their own network, guest Wi-Fi on its own range. Separation also improves security, and it is often the better engineering answer.
Enlarging to /23 is right when the devices genuinely belong on one network — one office, one team, everything needing to reach the same servers and printers. Choose the step for the right reason, not as a reflex.
Moving from /24 to /23 changes the mask from 255.255.255.0 to 255.255.254.0. The street doubles: addresses 192.168.0.0 to 192.168.1.255 now form one network with 512 addresses, 510 usable. Devices in 192.168.0.x and 192.168.1.x can finally talk directly, with no gateway between them.
Two details catch people out. First, the network address becomes 192.168.0.0 — a /23 must start on an even third number, so the old 192.168.1.0 becomes an ordinary usable address inside the bigger street. Second, every device must learn the new mask. A PC still carrying 255.255.255.0 will treat half the office as 'outside' and misbehave in exactly the one-way pattern masks always produce.
ipconfig /renew instead of waiting days for leasesDo this in a quiet hour, keep the old settings written down, and the change is a calm twenty minutes instead of a Monday-morning mystery.
The video's street-and-house picture is the key to this whole topic — watch it before planning any subnet change.
▶️ Watch Full VideoA /24 network has 256 addresses in total and 254 usable for devices, because the network address (.0) and broadcast address (.255) are reserved. Remember that phones, cameras, printers and spare devices all count against that 254.
A /23 with mask 255.255.254.0 joins two neighbouring /24 blocks into one network of 512 addresses, of which 510 are usable. For example, 192.168.0.0/23 covers 192.168.0.0 to 192.168.1.255, and devices across both halves can then talk directly.
Not always. If the pressure comes from devices that do not need to be on the office network — CCTV cameras or guest Wi-Fi, for example — putting them on their own separate network is often better than enlarging, and safer too. Enlarge when the devices genuinely belong together.