Someone Else Using Ip Address
How to fix your network when you see ‘Another device is using …
Internet networking involves a lot of alchemy, and I confess to occasionally dropping an eye of newt (or an IP of newt) into a boiling pot to fix problems on my local network. There’s a particular message that macOS displays in limited cases that perplexes people, because it’s the sort of low-level bubbling up that Apple generally takes care of. In this case, your Mac is alerting you to a problem that may be of your making or might involve your Wi-Fi gateway or broadband modem. That message: “Another device is using your IP address. ”
This conflict prevents your computer from accessing some of the local network and from reaching the internet. Here’s why.
Every device that communicates over the internet needs a unique internet protocol (IP) address, a number that is used by routers to package and send data to the right recipient. That’s true on a LAN or within top-level internet data exchanges, and whether it’s a $10 million router or an addressable smart lightbulb. When the internet first began its superfast growth over two decades ago, the addresses used came from a relatively small range, using the IP version 4 (IPv4) standard. The number of possible unique addresses was far smaller than what people predicted would be needed shortly, and that prediction came true.
Network Address Translation (NAT) was created as a way to offer LAN-connected devices something special while preserving the pool of addresses available. While most IP addresses have to be unique, because they’re all used in a big public pool—like having a unique street address in a unique city in a unique state or province—the NAT protocol allows for private addresses that are passed through gateway that maps the private address onto a shared public one. Outgoing traffic is managed by the router so that incoming responses are passed back to the right computer or other hardware on the LAN. It’s a tricky process, but it’s used for trillions of data packets a day globally (maybe quadrillions).
Most routers pair NAT with DHCP (Dynamic Host Configuration Protocol), which automatically assigns addresses to devices when asked. You’ll note that when you connect to a Wi-Fi network or plug in via ethernet on your network (and on most networks), you aren’t asked to configure IP settings. Instead, your device is set by default to send out a query to the gateway over DHCP; the gateway receives it, the NAT system finds an available address and keeps a record of it, and the DHCP server provides that address and other settings to your hardware, which is called a “lease. ”
Here’s several methods to solve the address-in-use problem.
If you don’t manage your gateway
If a family member, friend, or colleague manages the gateway—even as simply as they’re the one who has the password and they’ve never touched it since setting it up—ask them for help and have them read this article.
Power cycling the router might help if it’s a fault in the router’s internal tracking of addresses. Connecting to the router’s administrative interface can also assist in troubleshooting what’s going on.
Sleep and wake your Mac
If you’ve never touched your gateway settings, you can simply try putting your Mac to sleep and waking it; that sometimes clears a transient conflict. When the Mac wakes without an IP address, it tries to get the gateway’s DHCP server to give it an address again, and it may just work.
You could try restarting your computer, but that step may not be required; try the next solution instead.
Renew DHCP lease
In macOS’s Network preference pane, select your network adapter in the list at left and click Advanced, then TCP/IP. Click the Renew DHCP Lease. If this works, you’re all set (for now). If not, proceed to check for other problems.
Manually configured address
Every device has to have a unique private IP address on the local network, and if you’ve manually configured your hardware’s network settings to use a specific number, it’s possible you’re seeing the “Another device is using your IP address” alert because the DHCP/NAT combination has assigned out an address you set by hand for the computer you’re on. (Or, the other machine that’s using it was manually configured and you or someone else needs to check that one. )
For instance, you might be running a game server or want to screen share with your computer remotely, have read up on port mapping or UPnP (Universal Plug ’n’ Play), and configured your machine to have a fixed (or “static”) private address so that it could always be reachable via some router magic. You might have, say, set your computer’s address to be 192. 168. 1. 100.
Many gateways let you set aside specific addresses (sometimes called “DHCP reservations”) to avoid re-using an IP on the network. Others let you set the start of an IP range. So if the network is 192. 0 to 192. 255, you can set the start of NAT-assigned addresses to 192. 100, and choose any available address from 192. 2 to 192. 99. NAT will still work and DHCP isn’t involved. (The. 0 and. 1 addresses are usually reserved, so you may have to start in this example at 192. 2. )
To check whether you (or someone else) configured your Mac this way in the past and simply forgot about it, open the Network preference pane, select your network adapter in the list at the left, and then click Advanced in the lower-right corner. In the TCP/IP pane, if the setting for Configure IPv4 is Manually, the address was entered by hand. Check your gateway to see whether you can change the range there, if you want or need to keep this setting.
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The TCP/IP tab lets you set an address for your Mac, which could lead to picking one already in use.
If you don’t know why it’s set that way and it’s not on a work network in which making a change might have an impact on co-workers, choose Using DHCP from the pop-up menu, click OK, and click Apply, and see if the problem goes away.
Not enough network addresses to hand out
Most routers are configured by default to offer somewhere between 100 and 200 addresses, because when the box was designed, managing that quantity was within the processing capabilities of the device or it was seen as a reasonable number. An older gateway, however, might have been set by default or configured by an ISP’s installer for as few as 50 dynamically assigned private addresses. In 2000, who could imagine a future in which more than 50 different pieces of hardware in a house would all need to connect to the internet?! Ridiculous.
The DHCP server not only assigns an address, but also attaches an expiration time to it. When the time runs out, the device can request a new address or the server can renew if the device is currently active on the network. Otherwise, that address is freed up and goes back into the pool. In some cases, even with hundreds of available private addresses, your gateway might exhaust its supply. It shouldn’t hand out an identical address, but things could go awry. (You might get no address, in which case your Mac creates a so-called self-assigned IP address, which starts with 169. 254. x. )
This exhaustion of numbers can occur if you have a lot of internet-connected devices, share a home or building that has poorly managed Internet service (because they really should have more addresses available or better DHCP timeouts), or a lot of people pass across your network.
Start with your router. Read the manual, log in to its administrative interface, and check its settings. It may show you a list of connected devices and the assigned private IP addresses. You can see if you’re exceeding the number it can assign, and may be able to simply increase that number. You may also be able to lower the timeout duration, so that it frees up addresses faster.
You might have to upgrade your router or make more complicated changes, but that’s unlikely for home and small-business usage. On most gateways, you should be able to bump the number to over 200, or make changes that let you assign out over 500 or over 1, 000.
This Mac 911 article is in response to a question submitted by Macworld reader Humberto.
Ask Mac 911
We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to including screen captures as appropriate, and whether you want your full name used. Not every question will be answered, we don’t reply to email, and we cannot provide direct troubleshooting advice.
What can someone do with my IP address? | NordVPN
There are dangers to someone knowing your IP address, but they’re rarely discussed. Criminals can use your IP to launch various cyberattacks and scams against you and others. Before we begin, however, let’s start with finding out what your personal IP address is: What is my IP? By the end of this post, you’ll know what to protect yourself against and discover ways to hide your IP address. Pretty can someone find my IP address? Your IP address is a unique string of numbers assigned to you by your ISP – like a delivery address for online traffic. If you connect to a different Wi-Fi or move house, your IP address will change along with your ISPs use dynamic IP addresses, which aren’t fixed to your device, but you can have a static IP if you wish to (you can learn more about different types of IP addresses here). For example, if you want your computer IP address to always stay the same, you’ll be able to specify that through the device’s settings. This can be useful when port-forwarding, if you want certain data to be sent directly from your router to your computer IP your IP address holds certain information about you, someone may want to use it for malicious purposes. There plenty of ways people can get hold of your IP address. Here are just a few:If you torrent files. When you download content from torrent sites, every member of the swarm (total seeders and leechers) can see your IP address. All they need to do is check the list of borrowing your device. If somebody borrows or uses your computer, they can find out what your IP address is in seconds, as there are countless free websites that let you do an email. If you send an email to someone, they can check the header of the message, which could contain your IP address. Yahoo! and Microsoft Outlook are known to include IP addresses in the email icking on a link. Any link you click on will need to provide your iP address for the server at the other end to deliver the content provided by the link. Whoever owns that server will see your IP a VPN hide my IP address? Yes, it does. A VPN completely hides your IP address and encrypts your internet connection. Even better, a VPN prevents third parties like your ISP from eavesdropping on your data. Your online activity cannot be traced back to you, giving you a powerful layer of rdVPN has more than 5500 servers in 59 countries, providing you with the best speeds available. With one NordVPN account, you can protect up to six different devices: smartphones, tablets, laptops, and more. You can also install it on your router and secure gadgets that don’t support VPN functionality can jump from one server to another in seconds, changing your IP address and masking your location. Protect your online privacy out NordVPN on the latest cyber news and tipsWhat can people do with your IP? While your IP address won’t give away sensitive information like your phone number or apartment position, hackers can still use your IP against you. If a cybercriminal knows your IP address, the consequences can be devastating:Someone can get your location and intrude on your privacy in real lifeYour IP address shows what city you’re in, so if someone ill-intentioned finds it out, you could be in trouble. Let’s say you’ve announced that you’re going on holiday on your social media. A criminal only needs to do a little extra digging to find your house and burgle it while you’re meone can use your IP to hack your deviceThe internet uses ports as well as your IP address to connect. There are thousands of ports for every IP address, and a hacker who has your IP can try all of those ports to brute-force a connection, taking over your phone for example and stealing your a criminal does get access to your device, they could also install malware on it, which could expose your meone can impersonate you to get hold of your IP addressYour ISP could reveal your IP address to someone else. Criminals who know your name on social media can contact your ISP and try to impersonate you or use a vishing attack to steal your personal details. Remember that telecom operators are only humans who use systems with vast amounts of personally identifiable information. Employers can track your activityIPs are owned by ISPs, and each IP is assigned to a user. When you’re connected to your work network your employers could potentially see and track everything you do online – giving you hardly any privacy at all. A hacker can hit you with a DDoS attackIf a hacker has your IP address, they could harm you with a DDoS (Distributed Denial of Service) attack. A DDoS attack uses an army of computers controlled by a hacker to flood your device with traffic so it disconnects from the internet and completely shuts bercriminals can frame you for illegal activityHackers are known to use hacked IP addresses to download illegal content that threatens national security as well as anything else they don’t want traced back to them. Protect your IP address, and you will protect do I stop someone from using my IP address? You should always protect any personally identifiable information even if you think the risks do not apply to you. With enough determination, a bad actor can stitch together an entire identity just by going online, and your IP could be the starting are three ways to protect your IP address and prevent yourself from being exploited by hackers: Change your privacy settingsChange the settings on all your instant messaging as well as any other apps to “private” and don’t accept calls or messages from people you don’t know. Hackers are known to gain access to your IP address through messaging apps like Skype. Update your firewall and routerA criminal can hack your router remotely and retrieve your IP address, especially if you’re still using the default one. Change the password of your router regularly and be sure to use a long mix of upper and lower case letters, numbers, and special characters. Use a VPNA VPN will protect your IP address and your private information. By routing your online data through a VPN server with its own IP address, you can prevent websites from logging information about your device and location. While you might be principally interested in VPNs for their IP-switching functionality, they also come with a range of additional other benefits can a VPN offer? A VPN will establish an encrypted tunnel between your device and a VPN server. That means that no one can spy on your data as it moves from your device to the server — not even your internet service provider (ISP) has never been more valuable. Your ISP can monitor your activity and sell that information to advertisers and other third parties. Hackers can steal your passwords and use your private details to launch phishing attacks. It’s vital that you protect your rdVPN provides a number of extra features that you might find particularly useful. Our CyberSec system will enhance your protection against malware by shielding you from high-risk websites and other known threats. When Kill Switch is enabled, you can avoid any unexpected data exposure. And with the NordLynx protocol, you can enjoy unrivaled speeds, without compromising on out NordVPN on the latest cyber news and tips
Zen Bahar
Verified author
Zen likes to use her cybersecurity knowledge to help protect the privacy and freedom of others, otherwise, you can find her playing with paints in her studio in London.
Can my IP Address be used by someone else? | MacRumors Forums
#1
My IP address has shown up in an email from another person, can someone please tell me how this can happen
Last edited: Jun 2, 2011
#2
Your IP address is public. No, it can’t be used by anyone else.
#3
technically no, but thats granted others dont have access to your network, as your IP address is provided to you by your ISP.
#4
is there any way my IP address can be used by someone else, it has shown up on emails sent to another person
#5
If your IP address is a dynamic IP address provided by your service provider, then yes there is a chance that someone else can get the IP.
Keep in mind that only one network device(ex; computer) can have the IP address at any one point in time.
Cheers!
#6
Yes, someone can find out what the IP address is, but they can’t use it for anything. It only identifies the computer that it belongs to.
#7
How did you even discover this?
#9
It depends which IP address you mean.
If it’s your LAN IP address – the IP of your computer on your home network – then it’s very likely that someone else will have that same IP. If you’ve got a home network, and it’s based off a router using default settings, then chances are you’ve got an IP like 192. 168. 0. 2 or 192. 1. 10. That’s because the routers are factory configured to provide those IPs to any device you connect to them (they’re ones used by the Netgear and Belkin routers I’ve used, other brands may differ). So for example, anyone with a Netgear router using default settings is probably using 192. n addresses. This is possible because they’re only used on your home network – they’re not attached to the internet. All the internet sees is the WAN IP address of your router, not your computer.
If it is your WAN IP address (the one you see when you go to) then this could be because you have a dynamic IP address. If your ISP issues dynamic IPs (in the UK it’s quite common, don’t know about elsewhere) then you could easily have different IPs every time you connect; which would also mean that someone else will get your IP at some point (as you would theirs).
Those are the two most likely ways to see your IP somewhere else – does that help?
Frequently Asked Questions about someone else using ip address
Is it bad if someone is using my IP address?
IPs are owned by ISPs, and each IP is assigned to a user. When you’re connected to your work network your employers could potentially see and track everything you do online – giving you hardly any privacy at all. If a hacker has your IP address, they could harm you with a DDoS (Distributed Denial of Service) attack.
Can your IP address be used by someone else?
Your IP address is public. http://whatismyipaddress.com/ No, it can’t be used by anyone else.Jun 2, 2011
How do I find out if someone else is using my IP address?
How to Find Out Who is Using My IP AddressVerify that a system has an overlapping IP address. … Access a Windows command prompt. … Type “ipconfig” into the command prompt. … Look in the output of the command to identify the IP address assigned to your network interface. … Turn off the computer.More items…
