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198 votes

DDoS: Why not block originating IP addresses?

Let's say that you run a shop. Every day, you might get a few hundred customers. One day, you get tens of thousands of people coming in, who get in the check-out line, buys a trinket, and then gets ...
user128269's user avatar
  • 1,331
168 votes
Accepted

Is there any actual security benefit to restricting foreign IP addresses?

The concept is "reducing the threat surface". If there is an expectation that no connections will be made from a certain geographic area, then it makes sense to block that area, because, by definition,...
schroeder's user avatar
  • 131k
164 votes
Accepted

Can someone steal my IP address and use it as their own?

Network engineer with Border Gateway Protocol (BGP) experience here. Yes. But usually the attack would have to be for a larger address block and (as Eevee commented) require an attacker with ...
Darrell Root's user avatar
  • 1,492
117 votes

DDoS: Why not block originating IP addresses?

TL; DR The multiple source IPs are what makes them so hard to defend against. For the longer answer we look at the name. DDoS attack. That first D stands for distributed. In other words, there is no ...
HashHazard's user avatar
  • 5,185
92 votes
Accepted

Can a hacker, that knows my IP address, remotely access accounts I have left logged in on my computer?

No, they would have to have access to your browser cookies in order to abuse them to log into a site you left logged in. Merely knowing your public IP address would not allow them to log into any ...
forest's user avatar
  • 67k
91 votes
Accepted

Is it possible to spoof an IP address to an exact number?

You can change your IP to whatever you want; that's trivial. But that will not work the way you want to. Let's say the store's ISP is Apple Networks, and their IP range is 1.2.3.0 to 1.2.3.255. You ...
ThoriumBR's user avatar
  • 54.6k
75 votes

Can someone get my home address if I click on a link to a IP logger?

First: almost every single site out there is an "IP logger". Every server logs at least this information: IP address of the client Browser type and version Operating system Which site they came from (...
ThoriumBR's user avatar
  • 54.6k
72 votes
Accepted

Can I change my public IP address to a specific one?

You can send out a packet with whatever IP address you like. Then, one of the routers along the way might decide the packet makes no sense (it is a "martian packet") and discard it. Consider ...
LSerni's user avatar
  • 22.9k
71 votes

What does a website see if I am connected on my native IP and then enable my VPN?

Since you asked specifically what the website will see, rather than any intermediary watching your network connection, we should think in terms of requests: Your old ("native") IP will disconnect any ...
IMSoP's user avatar
  • 3,910
70 votes
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How fast can hackers change their IP address?

Botnet If someone has access to a botnet, even a small one, they could change the IP that their actions are coming from several times per minute or flood their actions from a million IPs in any given ...
schroeder's user avatar
  • 131k
69 votes
Accepted

More than three domains hosted on the same IP address

This is not a sign of a problem for your server. There's an important detail here, which is: 104.27.182.86 is not your server. That IP belongs to cloudflare. Cloudflare provides a large number of ...
Conor Mancone's user avatar
63 votes

Tracing the location of a mobile IP from an email

The problem with this scenario is that emails are typically not sent from the device itself, but from a central service. In order to do what you want, the investigators would have to make a few hops:...
schroeder's user avatar
  • 131k
59 votes
Accepted

How do hackers find the IP address of devices?

Connecting 'things' to the Internet is becoming common because of the benefits of remote communication. You can have your camera upload its footage to a cloud storage server, or be able to view the ...
schroeder's user avatar
  • 131k
54 votes

Is it a bad idea to bypass login wall for a specified IP address?

You don't have to worry about spoofing the IP from a different connection, because returned TCP packets would not make it to the attacker in that scenario. So all you have to worry about is how easy ...
700 Software's user avatar
51 votes

How did the brute-forcers get my IP address so quickly?

An IP address is nothing private. Nowadays it's possible to scan the entire IPv4 Internet within minutes. ZMAP, for example, is a tool that can be used for such scans. NMAP can be used on IP addresses ...
Valentin's user avatar
  • 651
48 votes

What information can you get with only a private IP address?

Private IP addresses as defined by RFC 1918 (10.0.0.0/8, 172.16.0.0/12 & 192.168.0.0/16) can be used as anyone wishes, so a private IP address alone does not tell much and nothing is definite. ...
Esa Jokinen's user avatar
  • 19.1k
46 votes
Accepted

Are certificates without DNS fundamentally flawed?

However, in this scheme, couldn't an impostor just present the certificate after getting it from the real server? An impostor cannot present, and take advantage of, the real server's certificate ...
gowenfawr's user avatar
  • 73k
44 votes

Tracing the location of a mobile IP from an email

If the police have an email, sent by a suspect over a 3G or 4G network, could they use the IP address (since they know when it was sent) to find out - from the service provider - the precise location ...
Mark Buffalo's user avatar
  • 22.6k
43 votes
Accepted

Is it practical to pre-blacklist certain GeoIP regions?

It's essentially a business decision, rather than a security one. The risks from a business perspective are that you lose users from that country, or who are accessing the site from VPNs located in ...
Matthew's user avatar
  • 27.4k
40 votes

Can someone steal my IP address and use it as their own?

If someone manage to get a backdoor program installed on your computer, they can route all their traffic through it using it as a proxy server, thus "stealing" your ip. All their activity will show ...
IcaroAugusto's user avatar
36 votes

Which IP address would be most safe and suitable to use as a placeholder in a live system?

I recommend using an address in one of the TEST-NET networks (192.0.2.0/24, 198.51.100.0/24, and 203.0.113.0/24) documented in RFC 5737 and RFC 5735 (link below). Pay attention to the Operation ...
kenlukas's user avatar
  • 2,125
34 votes

How fast can hackers change their IP address?

No one seems to have addressed this yet, but I'd like to introduce the biggest problem to IP based rate limiting: IPv6. If you (naively) applied the same logic as you do to IPv4 addresses to IPv6 ...
Allison's user avatar
  • 4,035
32 votes

More than three domains hosted on the same IP address

This is perfectly normal. There is a big shortage of IPv4 addresses. In fact, we should have run out of them a long time ago. But since so much infrastructure is based on IPv4, it keeps getting "...
manassehkatz-Moving 2 Codidact's user avatar
29 votes
Accepted

Is my iPhone being targeted by the US Department of Defense?

I don't believe you (or anyone else) is targeted by the US Department of Defense. More plausibly, AT&T screwed up something on their server. A very quick research on the number 1111301000 returns ...
Andrew T.'s user avatar
  • 577
29 votes

Can two locations in the same city at the same time have the same IP adress?

Details here depend on your specific ISP setup, but it might well be that multiple customers share the same public IP address. This is called NAT or in case of ISP CG-NAT (carrier grade NAT). It is ...
Steffen Ullrich's user avatar
28 votes

Someone has my ip address and is threatining to find and leak my personal information

Don't worry too much It is relatively easy for someone to get your IP address, they just need to get you to visit a website they control. Some forums let people include links to images, which your ...
paj28's user avatar
  • 33.8k
27 votes

How do hackers find the IP address of devices?

It's now possible to scan the entire IPv4 Internet in a matter of minutes using a tool like ZMAP or masscan Likewise they can use online databases like Shodan and scans.io to find huge lists of a ...
Trey Blalock's user avatar
  • 14.2k
27 votes

DDoS: Why not block originating IP addresses?

In addition to @Hollowproc's excellent answer, the actual "addresses" being used as sources are often spoofed in an attack like this. An attacking host can pretend to be any number of other IPs, ...
gowenfawr's user avatar
  • 73k
25 votes

Securing a LAN that has multiple exposed external Cat 6 cable runs?

Options that come to mind: Use a Managed Switch to provide access control by physical port. For each physical port, only a specific IP address can be allocated (i.e. that of the camera) This may ...
700 Software's user avatar

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