Helping people with computers... one answer at a time.
If it's certain that a neighbor is using your IP address without permission, you need to take steps. But first, you need to make sure.
My neighbor used my IP address to send out emails. How does this work? Can I change my IP address? I have googled this topic and the answers are very confusing.
•
It all depends on how you think he got your IP address, and in fact whether it's really yours at all.
There's at least one common scenario where this does represent a true security risk, and we need to nail that down. But there are also scenarios where it's not really an issue in your control.
•
If your neighbor is truly using your IP address, that implies he's connected to your network. That's a bad thing, unless you trust him and have explicitly allowed him to do so. I'm guessing from your question that's not the case.
By far the most common reason for this is simply that you have an "open wireless hotspot":
|
It's important to note that your neighbor could be completely unaware - it can happen accidentally or if he's not paying attention to what he's connecting to. I would not assume malicious intent on his part, unless you have additional information that says otherwise.
The fix is very simple: password protect the wireless connection. Configure the wireless router or access point to use WPA which then requires a password to be able to connect to the wireless network. Of course don't tell your neighbor that password.
No one except those you've authorized will be able to connect to your network.
As a bonus, your connections will be encrypted, and no one will be able to "sniff" them either, as is possible at most free wireless hotspots.
•
There are a few other reasons that he might appear to have sent email "from" your IP address.
You could have misread the email headers - your IP address, as the destination when you download your email, may well appear within it, in addition to the IP and email address that the mail was sent from.
You and your neighbor could have the same ISP, and both have "DHCP" assigned IP addresses - which can change. In fact, what's your IP address today could easily be your neighbor's IP address tomorrow.
The email might not be from your neighbor at all. Your machine could be infected with a spam-sending virus or bot, and it could be "spoofing" the from address so as to appear that it's being sent by your neighbor.
•
Can you change your IP address? Well, that too depends - this time on what kind of IP address you have.
If you've been assigned a static (unchanging) IP address, you'll need to contact your ISP and coordinate getting it changed with them.
If you have a dynamic IP address (DHCP, above), then you can try to change the address by simply unplugging your internet-connected modem and/or router, waiting a while, and plugging it back in again. This way it will ask for a new IP address. The problem here is that there's no way to force it to be different than whatever you had before - you may get the same IP address again. In fact, many ISPs explicitly try to give you the same IP address for "a while", even when you're not connected for a time, as it can be slightly more efficient for them.
Article C3814 - July 19, 2009 « »
Leo A. Notenboom has been playing with computers since he
was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed.
After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers
to common computer and technical questions. More about Leo.
July 22, 2009 9:34 PM
All of the comments are great and true.
Another way to secure your wireless is to Disable your SSID broadcast.
....Robert
23-Jul-2009
July 23, 2009 9:53 AM
You may be surprised to know that in my country many ISP (They call them ISP) provide IP address to customer directly from there switch/hub with more then /29 subnet! Also many customer in same subnet and there is no protection at all! yes this is true. If asker is in this scenario, I would suggest him/her to change that 'unsecured' ISP. I worked for my Government's Cyber Security Department for while and found it is very common practice among ISP's in my country.
Bauani's Tech Blog
July 25, 2009 12:48 AM
I filled a form with my phone number and house address.when connecting wireless.now anyone can look up my e-mail address and get my name,phone number and physical address.Is there anyway for me to erase,hide or change the information ?
25-Jul-2009
August 10, 2009 3:26 PM
if you know how many computers will connect to your network, can you restrict this number? Would such a restriction only be applicable, though, assuming all of your computers(full capacity of allowed connections) were filled and active at all times the network is active?
Also, a question about networks. I am connecting to the Internet using a wireless router which is connected to a cable modem. I have disabled file-sharing on my computers. Is this strictly a Wireless Internet Access point then? How can I tell if the computers which use this wireless access to the Internet are exposed or able to be explored by any other computers using this connection?
February 1, 2010 3:28 AM
My neighbour has an open system, when I (out of interest of course)I had a look at her router settings, I found my computer name under LAN clients, does that mean she would be able to access my computer?
Bob.