What Happens If Your IPv4 Lease Isn’t Renewed?

An expiring lease should not become a customer outage.

When a DHCP lease expires without renewal, the device stops using that IPv4 address and starts obtaining a lease again. Services using that address can lose connectivity until the device has a usable configuration. A successful renewal before expiry normally keeps the same address and lets the customer carry on working.

If you are an ISP, hosting provider or cloud operator, there is another renewal to plan: the IPv4 service you obtain from your supplier. Its end date is separate from a device’s DHCP timer. Renewing DHCP does not renew your commercial address supply, and renewing your IPv4 service does not repair a local DHCP outage. Knowing which layer needs attention gets your team to the right fix faster.

The real cost is the service behind the address.

An IP address connects to much more than a router configuration. Customers build applications, access rules and working habits around it. If that address stops working, the impact can spread:

• Interrupted work: VPNs, remote desktops, calls and file transfers using the affected address may disconnect. API requests can fail or need retrying.
• Time spent changing settings: a different public address can mean updating DNS, customer allowlists, monitoring, firewall rules and partner integrations.
• A new address history: moving mail or other reputation-sensitive services can introduce fresh deliverability and reputation work. Expiry itself does not instantly damage an address’s reputation.

For a commercial IPv4 service, a missed renewal can ultimately mean losing use of the block and moving services. Routing and resource handling follow the supplier’s service process, not the 50% and 87.5% DHCP timers. Put the continued use of your addresses into the purchasing decision before customers depend on them.

Choose your IPv4 around the business you want to keep running.

LARUS brings first-party IPv4 supply, address operations and Continuity into one relationship. Your team gets a direct operating partner for the addresses that support customer services, rather than spending its time carrying an issue between suppliers.

When long-term address use is essential, Continuity Critical includes Guaranteed Renewal. Choose the Continuity service around the importance of your workload, with the operating support and escalation path your team needs. The aim is practical: spend less time preparing for disruptive renumbering and more time serving customers.

For carriers and ISPs growing their networks, Network Partner brings Unlimited IPv4 together with automated allocation and API control. Address growth and renewal continuity answer different operational needs; LARUS lets you plan both around the business you are building.

LARUS is the world’s only IPv4 platform built on court-recognized shareholder rights in the RIR system. See the foundation behind LARUS Continuity and choose the partner you want standing behind your network.

How DHCP renewal keeps devices connected

DHCP supplies an address and network settings such as the subnet mask, gateway and DNS servers. A dynamic lease allows the server to reuse addresses after devices leave. Renewal normally happens automatically while the device continues using its current address.

DHCP renewal timeline

Stage	What the device does
T1 — normally 50%	Sends a DHCPREQUEST to the original server to extend the lease. One missed reply does not immediately disconnect the device.
T2 — normally 87.5%	If renewal is still unsuccessful, broadcasts a request to reach a server that can renew the lease.
DHCPACK received	Applies the confirmed lease and its timers. Successful renewal normally retains the address.
Lease expires	Stops using the expired address and returns to address acquisition. The address may become available for reuse.

The server can supply different T1 and T2 values. After expiry, the usual acquisition exchange is DHCPDISCOVER → DHCPOFFER → DHCPREQUEST → DHCPACK. If the old address is still available, the server may assign it again. A different address is possible, so services tied to the previous address need checking. See the DHCP renewal specification.

Why a working network can miss renewal

Lease expiry is often the visible symptom of another fault. An unavailable DHCP server, a broken relay, a VLAN change or a firewall rule can prevent requests and replies from reaching each other. An exhausted address pool can also prevent new allocation during recovery.

Lease length affects how much time the team has to respond. Shorter leases suit busy guest networks where addresses must be reused quickly. Longer leases can suit stable device populations, but they do not replace server availability, capacity monitoring or tested failover.

Recognise the pattern and restore service faster

• Wi-Fi looks connected, but applications fail: check the IP configuration and gateway, then whether the client can obtain a lease. A radio connection alone does not prove working IPv4.
• One VLAN loses clients: inspect that segment’s relay, scope and forwarding path before changing the whole network.
• Many clients fail after maintenance: compare their expiry times with DHCP server availability. Existing leases can hide a server fault until clients need renewal.
• A device moved networks: it may need a new configuration on the destination network; moving between access points on the same network does not by itself require a new address.

Fix the connection, not just the symptom.

Start with the affected device’s address, lease times, gateway and DNS. Compare it with a working client on the same segment. Check server and relay health, the relevant address pool and the DHCP traffic path, including UDP ports 67 and 68. Once the cause is resolved, renew the lease and verify the customer’s application from end to end.

If your only access to a production device is the affected network connection, arrange console or out-of-band access before releasing its address. That keeps the repair in your hands. For a public-block service nearing its end date, contact the address supplier about renewal and routing continuity instead of repeatedly restarting DHCP.

Build continuity into everyday operations.

1. Make DHCP resilient. Use a coordinated redundancy or failover design and verify that each client segment can reach it.
2. Match leases to the network. Balance guest-device turnover with the stability needed by fixed workloads; use reservations where a device needs a predictable assignment.
3. Catch problems before expiry. Monitor failed renewals, pool utilisation and server health. Test maintenance and recovery with representative clients.
4. Plan public-address continuity early. Know which applications, APIs and customer access rules depend on each block. Choose the operating partner and renewal service before an end date becomes a migration project.

Keep IPv4 dependable while your network evolves.

IPv6 can provide another working path in a dual-stack network, but IPv4-dependent applications still need usable IPv4. Treat address assignment, public routing and supplier renewal as parts of the same customer service, with clear monitoring and a tested recovery path. More background: IP addresses and DHCP.

IPv4 lease renewal questions

Will I always get a different IP after a lease expires?

No. The server may assign the previous address again if it remains available. Check the new configuration before assuming that DNS, allowlists or remote-access settings need changing.

Does a failed renewal immediately take me offline?

A failed request before expiry normally leaves the existing lease usable. If the lease expires without renewal, the device stops using that address. Other interfaces or a working IPv6 connection may remain available.

Why does my device show 169.254 instead of its usual address?

Some devices select an IPv4 link-local address when they cannot obtain a usable DHCP configuration. It supports communication on the local link, not normal routed internet access. Check the DHCP path; RFC 3927 explains link-local addressing.

Will a reservation, static IP or reboot solve renewal?

A DHCP reservation gives the client a predictable address but still uses DHCP. A manually configured static address has no DHCP lease timer, yet still needs valid network configuration and continuing public-address service. Rebooting may retry acquisition; restore the underlying server or network path for a lasting fix.

How does LARUS help me keep using my public IPv4?

LARUS combines address supply and operations with a choice of Continuity services. Critical includes Guaranteed Renewal for businesses built around long-term address use. Choose the plan that keeps your team focused on customers instead of planning the next renumbering exercise.