Windows message saying 2 Pc's using my IP.

joe134

Hi guys, I have just had a dialogue box, saying Windows detected there is another Pc on my network using the same IP address, see administrator.(me)?
I do have an I=pad, which is on at the same time, usually by OH..
Is it this, or something more sinister.?
Is someone Piggybacking?
Had a slight hiccup on both today with connection to the net, unusual.;rebooted router, then ok.
I use ethernet on my laptop, all the time, not wifi.
Any advice would be grateful.

psychic_teabag

In a typical setup, your computers are assigned IP addresses automatically by the router (via the dhcp protocol). So two computers should not get the same address. It could possibly happen if one computer could not reach the router when it was starting up, and decided to just use the previous address it had.

But it could conceivably be someone breaking into your wifi. If you can log into your router, you should be able to see which devices are currently connected, and what addresses they are using.

Computers typically use 'arp' to store mappings from IP address to mac address (the actual hardware address assigned to the network interface). You should be able to ask windows to show you its arp tables, but I don't know the command offhand. Could try just arp in a dos box.

joe134

psychic_teabag wrote: »

In a typical setup, your computers are assigned IP addresses automatically by the router (via the dhcp protocol). So two computers should not get the same address. It could possibly happen if one computer could not reach the router when it was starting up, and decided to just use the previous address it had.

But it could conceivably be someone breaking into your wifi. If you can log into your router, you should be able to see which devices are currently connected, and what addresses they are using.

Computers typically use 'arp' to store mappings from IP address to mac address (the actual hardware address assigned to the network interface). You should be able to ask windows to show you its arp tables, but I don't know the command offhand. Could try just arp in a dos box.

Thanks for reply.
As ipad is the one on wifi, then, it could be that.
Not sure how to get into router to do as you say.?
Had ipad 18 months, this is the first time it's happened
? Could be as you say.
Will try router tomorrow
Keep getting another box, saying , USB device not recognized, but had that a while, I think it's a dodgy camera on my Pc.?
Composite Device;;
Seems all at once.:beer:

[Deleted User]

psychic_teabag wrote: »

Could try just arp in a dos box.

That will work.

Alternatively, you could just change the WiFi Password, thereby locking out any unauthorised users.

Indeed, it's a good idea, to change the Password from time to time anyway.

GunJack

it's highly unlikely to be outside interference, just reboot one of the devices and it should pick up a new IP address from the router

Big_Graeme

Check the PC doesn't have a static IP assigned, I've found this to be the main cause.

S0litaire

What router are you using?

Their might be an option in advanced settings to link an up address to a wireless or network cards "MAC address".
It's half way between letting the router pick an IP address all the time and a fix address on the PC.

jshm2

If you have a static IP then it can happen with some ISP's Best bet is to phone your ISP if this is the case. Do not mess around with your router if you don't know what you're doing.

joe134

Thanks all for replies
".Could try just arp in a dos box."
Don't know anything about arp?
As it was Windows that notified me, this would apply to my Pc only wouldn't it which is ethernet.over my head this bit;;;
Sorry I'm a bit vague on this matter, first time it's occurred.


As I know very little about routers, I'm tempted not to meddle, and take Gunjacks advice for present.If there is another Pc hacked into my Wifi, then won't Windows inform me again?
Reckon I will never be sure my Router is safe ?

Didn't know you had static IP address? or could change them?
I thought, every time you logged on, you changed IP's, whatever you were given.
How do you find out if your IP is static?
If they are both logged on,at the same time, DO they both have the same IP address?? Can you monitor your IP address??

It's a new Talk Talk Router. D-Link 3780 dsl wifi protected n adsl 2+
It has a default IP address on back.
Un and PW Admin, but got wifi pw and network name on a card.
Don't know how to get in this one?
Only time I've got into a router , was to lockon to a channel, HAUWEI, last one.

As my Pc is ethernet, and I bank online with my I-pad, it's the i-pad wifi I'm more concerned about.;;;;;

As I lost connectivity with both at a similar time yesterday,only briefly, and rebooted Router, which sorted it.
:beer:

kwikbreaks

Big Graeme is talking about the device itself being set up with a static internal IP but as you know nothing about them it won't be because the default is to obtain an IP from the DHCP server which will be your router. It is possible to specify that the router will always allocate the same IP to a particular device and that would be the usual way to achieve an internal fixed IP rather than hard coding one into a device.

Virtually all ISPs will allocate you a dynamic rather that static IP and that will be nothing to do with the problem you are seeing.

Amost certainly some sort of bug has caused this and following Gunjacks advice should sort it out. I'd also reboot the router first as that will have been the source of the problem and the general rule with most things computer related is to try a reboot first if anything goes wrong.

buglawton

My old Netgear router used to throw up this issue, got fed up and tried static addresses on all devices. Since moving to an Asus router and auto addresses again, never seen one instance of this problem.