Connected to Wi-Fi… but no Internet? Let’s talk DHCP lease issues

Wi-Fi
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Sometimes the Wi-Fi isn’t broken - the IP lease is.
:key: DHCP decides whether you truly connect

We’ve all been there - your phone shows full Wi-Fi bars, but apps won’t load, Zoom drops, and frustration kicks in. From a user’s perspective, “Wi-Fi is broken.” But often, the real culprit is not Wi-Fi at all - it’s DHCP lease management.

:magnifying_glass_tilted_right: What’s happening under the hood?
When a client joins Wi-Fi, it doesn’t magically get Internet. It needs an IP address via the DHCP DORA process:

:counterclockwise_arrows_button: DORA Process (in simple words):

  1. Discover – Client broadcasts: “Is there a DHCP server who can give me an IP?”
  2. Offer – Server responds: “Here’s an IP and other settings I can give you.”
  3. Request – Client says: “Yes, I want that IP. Please reserve it for me.”
  4. Acknowledge (Ack) – Server confirms: “Done. You can now use this IP.”

:white_check_mark: If all four steps succeed → device is online.
:cross_mark: If any step breaks (e.g., no Offer or no Ack) → Wi-Fi shows connected, but no Internet works.

:warning: Common causes of DHCP lease issues:

  1. Scope exhaustion – Too many devices, not enough IPs in the pool.
  2. Improper lease times – Too short = churn, too long = stale IPs.
  3. Sticky clients – Holding on to old IPs while roaming.
  4. NAT profiles with limited IP leases – AP/controller caps IP assignments.
  5. Relay or Option 82 failures – AP/controller doesn’t forward DHCP packets properly.

:hammer_and_wrench: How do you spot it?

  1. Device associates fine but shows “Connected, no Internet.”
  2. Sniffer capture: DHCP Discover packets sent, but no Offer/Ack back.
  3. Controller/AP logs: client shows “connected” but with blank IP.

:light_bulb: Best practices to avoid DHCP pain:

  1. Size DHCP pools with enough buffer for peak usage.
  2. Tune lease times (not too short, not too long).
  3. Monitor NAT profile IP lease limits on APs/controllers.
  4. Track DHCP success/failure trends in analytics.

Remember: Not every Wi-Fi complaint is RF-related—sometimes it’s the IP layer.

Connected to Wi-Fi… but no Internet?DHCP lease issues
Connected to Wi-Fi… but no Internet?DHCP lease issues985×584 135 KB

:loudspeaker: Takeaway:
When users complain “Wi-Fi is down,” the real issue might be DHCP lease failures. Understanding the DORA process helps us separate true Wi-Fi issues from backend misconfigurations.

:backhand_index_pointing_right: Have you faced cases where Wi-Fi looked perfect, but DHCP leases caused the outage? How did you troubleshoot it?

LinkedIn: :backhand_index_pointing_down: