Wifi „no internet connection“ issues (iOS16)

I have noticed that my phone is slow intermittently. It’s not the Wi-Fi because all of my other devices do not have the issue. I have a brand new iPhone 14 Pro and have contacted apple support. The last option is to send the phone in for repair which is where I’m at. If the phone gets sent anywhere it will be getting returned for a different manufacturer. This is my first iPhone and may very well be my last.

When this happens, it's almost always due to your phone not receiving a proper IP address via DHCP from your server, or not receiving appropriate gateway settings.

In either case, it's due to a failed communication between your device and your DHCP server.

Most times, that's your Wi-Fi router, but sometimes it's a different device on your network that's responsible for providing DHCP service.

Depending upon how tech savvy you are, you may want to check your DHCP server's logs to see if it's complaining about anything.

VPN connections will usually make Wi-Fi problems worse. If you can’t get it to work without using VPN don’t switch to VPN, instead troubleshoot the problem until it is resolved. VPN will just mask it and cause problems later if it isn’t resolved at the source.

There is a simple test you can do to isolate the problem: Try it on different Wi-Fi networks. Ideally friends or neighbors, but if not, reliable public sites like hotels, libraries, hospitals, Starbucks, MacDonald’s, etc. Avoid the “public” networks that are provided by cable companies; they are frequently pretty flakey. If the problem is only on your home network there is only one place that needs to be investigated.

If you suspect the DNS service from your ISP you can override it with a reliable public DNS, such as Microsoft (1.1.1.1, 1.0.0.1), Google (8.8.8.8, 8.8.4.4), or OpenDNS (208.67.222.222, 208.67.220.220)

I did do a factory reset on router, did not solve the problem. It is a newer (couple years) EA8300 linksys. ATM I just have wifi turned off on my phone because the slowness was annoying me. I do see other people complaining about it on various forums and twitter, but not a ton, as you mentioned in another comment. Have not tried any VPN stuff, as I normally do not use one, but I might try that later tonight. Thanks.

Sorry, the issue IS router related if it only happens with one router. Are you using a VPN connection? Try after deleting the VPN profile (just turning off VPN is not sufficient). Does your router have MAC filtering enabled? How many devices are connected to the router? Is the router’s DHCP address allocation block large enough for all of your devices? There are other possibilities involving router incompatibility, but these are a start.

Hi lawrence,

I am not using any vpn. There is no MAC filtering enabled. At most around 4 devices connects to router at the same time.

Sometimes even 2, when i face “no internet” issue.

Never faced issue while on iOS 15 and i have been using same router for like 8 months.

The issue only started happening after iOS 16. Other devices runs fine with iOS 15 and some windows devices.

Resetting/restarting router or forgetting network doesnt fix the issue. Issue is only fixed after i retsart my iphone. Therefore issue cant be with wifi router.

If anybody here thinks otherwise, just answer me why does restarting iphone fixes the issue(for some time) but restarting router doesnt?

I can give you a perfect example of how this can happen as I have seen and debugged it before, and that's a DHCP bug in the router.

How?

When your iPhone connects for the first time it will ask for an IP address from the DHCP server to be able to get on the network by sending a DHCPDISCOVER request. If it receives a DHCPOFFER it will continue the DHCP acquisition process, apply it and you're on the network.

However, from that point on the phone has state information and rather than ask for an address it will issue a DHCPREQUEST to renew the address.

If either side - the iPhone or the DHCP server - botches the renewal protocol, it will result in the exact behavior you are seeing.

To put it another way, imagine you are staying at hotel; when you check in you ask for a room for one night and they tell you which room you get and you move in.

But that same night you realize you need to stay an extra night, so you ask the hotel if you can get the same room for another night rather than just ask for "a room." A different sequence of events must occur at that point to get to stay in the same room another night.

If either side screws up, you will have to move out of your room by check out time and come back that afternoon to check back into the hotel.

I have seen both the DHCP server and, on occasion, macOS get it wrong, and frankly sniffing the DHCP packets from another host on the network and tracing through the protocol is the only way to find out who's at fault. Is the device sending an improper renewal? Is the server not responding with a proper DHCPACK?

No one could say without explicitly looking at the network traffic being passed.

Lawrence's response above is how you begin to diagnose what went wrong.

Hi Lawrence,

Thanks for the steps in detail.

Here are my findings when the internet again went down

•DHCP lease time is 24 hours.

•IP address before and after the internet went down was still same starting from 192.168.x.x.

• All three devices that were connected to router were assigned different IP adressess so none of them were colliding with my device IP address.

• DNS is configured to automatic. Changed it to manual and typed google DNS but still same “No internet Connection” issue.

• I dont use iCloud+ therefore private relay option isn’t available in iCloud settings.

• I didnt use VPN at the time this issue occured, but one profile was there. Deleted that profile but again issue didnt resolved.

• Had to restart iphone again to get this fixed again.

• Will connect with wifi hotspot device for a day and see if same behaviour occurs there.

Hi DogCow,

I have followed the steps suggested by Lawrence and provide my inputs.

Thanks for explaining above how this works.

I have one question, that if we assume that DHCP server was botching the renewal requests, then shouldn’t it botch the requests for other devices as well. Why is it doing this only for 1 device and how do we fix this?

What are the other devices? If they are always connected they don’t send DHCP requests. It’s only devices that are out of range of the network periodically that request IP addresses when they reconnect.

Hi Lawrence,

Other devices are iPhone XR running iOS 15 and 2 Windows laptop. All the devices including effected one are well within Wi-Fi router range as it is in home.

I have faced this issue, when I haven't left the Wi-Fi device range as the router and I were in the same room and then suddenly the internet goes down.