Can your IP address be a security issue?

[anonymous]

I heard that it can be a security/privacy issue if someone knows your IP address. What issues does it cause? How do people find out your IP, and how can it be used against you?

[Kasey]

Finding your location mostly, for national security reasons mostly, but people know how to use it tofind your address and if they know that they can have inappropriate items sent to your house (E.g sex videos, porn)

[only.lurking]

Contrary to what most people think, your IP address isn't some virtual social security number that, once discovered, will allow malicious individuals to ruin your life with the push of a button. Looking up an IP address WILL give you a general idea of where someone is, but that's as far as it goes with free tools. What someone sees is the city or region that your IP is registered out of (ever notice those popup ads that say stuff like 'Find singles in [your city] tonight!' and wonder how they know where you live?) Depending on your ISP, it may not even show up as your own city, but rather the nearest big city to you. That stuff you see on TV where the Feds track down hackers and break down their door with nothing but their IP is a little exaggerated, and they don't show the part where they contact the Internet Service Provider (the people you pay for your internet service) and serve them a warrant or request to get the account information of the person the IP is provisioned to. Frankly, your phone number is more likely to betray your personal location than your IP address ever will.

Any time you make a connection with anything online, the server that you're connecting to will know your IP. For example, if you visit http://www.whatismyip.com , you'll see your IP shown right at the top of the page. If you use something like Direct Connect on AIM or some other chat service, the person you're connected to can find your IP (normal conversations without Direct Connect don't share this information). Every time you send an e-mail, your IP address is included in the hidden header text of the e-mail and can be viewed by the recipient.

None of this is bad. This is what the IP address is for - it lets other computers on the internet find you. It's how you get e-mail, receive data and images from websites, and do... well, pretty much anything online.

That being said, the start of almost every "hacker attack" is by getting the target's IP. They have to find you before they can attack you. Once they know your address, the rest is up to how well defended your computer is. If you don't have the most recent updates for Windows or other programs that might connect to the internet for whatever reason, the attacker can exploit vulnerabilities in the program's code (Back in the day, you could break into someone's computer by pretending to be a website sending http information. Microsoft has long since patched that hole, though.)

Alternatively there may be a trojan or other piece of malicious software already installed on your machine that intentionally creates these vulnerabilities for hackers to exploit. These applications usually "phone home" and just send your IP out without you doing anything to trigger it, thus giving the malicious trojan-owner a target. Once connected, he'll have carte blanche` of your system and can basically do whatever he wants.

The best way to defend yourself against these attacks is to have a firewall running at all times. Recent Windows OS' come pre-installed with a firewall. Usually that's sufficient, assuming you keep it on and don't tell it to open itself up too much. If you're paranoid or want to actually see what the firewall is stopping, you can get free or commercial software firewalls that offer much more control and log/report all network activity they deal with. Routers also act as hardware firewalls, and make hacks much more difficult to perform.

Hope that helps.

[Robert H]

I'm not an expert, but when you have a static IP, yeah, it makes sense that a hacker who noticed you one day and tried hacking, will try again every few days for fun. If you have a dynamic one which is common with a simple household dsl account, you'll have a new IP address every 24 hours. A moving target. Not sure if it makes a big difference or not.

[Preacher of Light]

If you have a good virus software you should not be seen at all, unless you stop on a site. There is software hides your IP, but you have to have one for sites like a club, or member site. You have to show your IP or you don't get on the site. Hackers can check all your ports and take over your computer or plant a virus if they ping and find one.