Another device is using your IP address mac, what do I change my IP address too?

Our internet router often stops working at home, but for the the second time only I have got a pop-up error saying:

"another device is using your ip address".

We have an iPhone and a Macbook but as far as a remember this problem occurred for a brief time when we were without an iPhone. In any case, I had a look at this post which suggests the problem is a cause of the iPhone and Macbook trying to use the same address.

I changed the IP address via System Preferences > Network > TCP/IP > configure IPv4 Using DHCP with manual address to 11.11.11.11. I then switched back to Using DHCP and clicked 'Renew DHCP Lease'.

When I checked the IP address again it changed to 192.168.1.11. It works now but I wonder if this is a permanent fix or will this problem keep occurring?

Update: The problem persists, but his time without the error message which would leads me to believe that there another problem in addition to the "Another device is using your ip address" problem.

Solution 1:

Often times these issues can be solved by rebooting ALL computers (iPhones, Macs, etc.) on your local LAN. A reboot causes DHCP to request a lease. And your router should only hand out ones that are unused. So every device should get a unique address

HOWEVER it is possible that you have manually assigned an IP address to one or more devices, so check for that. Make sure all are different and all are on DHCP.

ALSO possible, someone unwanted is on your network. Change the WiFi password just in case.

Failing all of that assign everything a static IP address like this

192.168.1.x

Where x is as follows

between 2 and 254 unique (only one device has any one number) Your subnet mask is likely 255.255.255.0 Your Gateway is likely 192.168.1.1 (your cable modem or WiFi access point) Your DNS will vary

The last three should be listed in your network System Preference and will be the same on all devices (only the IP address must be different). Select the connection (WiFi) and click Advanced, then the TCP/IP and DNS buttons. Record the subnet mask, gateway and DNS servers. Then fill that info in on all devices.

It would be a good idea, if you do this, to make a note of all the settings and which device gets which address. Keeping track can be a pain, which is why we have DHCP. It is supposed to hand out all that info automatically. So it is likely that there is a device on your network NOT set to DHCP.

Solution 2:

Check on your router which other computer or phone is using your IP address. Note your actual address, let's say it is 10.0.2.1. Look at your router ARP table and note the MAC address associated with your IP address 10.0.2.1.

If this MAC address belongs to one of your equipment

then everything is OK. Just check that this equipment is actually within reach of your router and make it renew its DHCP lease. For example on an iPhone, if your home network is named home_Wi-Fi this is:

Settings > Wi-Fi > home_Wi-Fi > DHCP > Renew lease

If the same IP address is regularly attributed to 2 different equipments connected through Wi-Fi, this may be caused by a poor quality wireless connectivity. Here is the scenario which might be at play:

• 10:00 alice get address 10.0.2.1 from the router, with a lease time of 4 h
• 10:30 alice goes in the living which is on the border of the wireless network and loose her connexion, but she doesn't care because she is just wotking on a heavy presentation with Keynote
• 14:00 the router expires the lease attributed to alice
• 14:30 bob ask a new DHCP address to the router and get 10.0.2.1

• 15:00 alice goes in the kitchen which is inside of the wireless network and automatically use her actual IP address which is still 10.0.2.1

  ⇒ duplicate IP address detected

If this MAC address doesn't belong to one of your equipment

then you have a neighboor who is hacking your network.

In such a case, I advise you to fire a new interesting question:

How to get rid of my wireless scroungers?