ISP can tell what my internal network ip's are?

In summary: Query is a javascript library that allows you to do things like create a slide show from a set of images, or to build a simple form validation library.In summary, the ISP technician told me that my internal network ip's are visible to him because I use a router. He said he sees more then one IP address. I switched to using OpenDNS to resolved the domain names.
  • #1
fargoth
320
6
ISP can tell what my internal network ip's are?

To make a long story short, I use a router, with two computers behind it, I called my ISP for technical help, and the technician there told me I use a router (which is a reason for him to not help me..). He said he sees more then one IP address!
how can it be possible?!

I suspect he pulled a nasty trick on me - when i use a single computer and connect directly through the modem, (via DHCP, i have an "always on" connection) i can resolve the domain names just fine.
but through the router i can surf only to the sites which are still in the DNS cache...

I switched my router to use the OpenDNS servers, and now the problem is over.
but i got the feeling something fishy took place...
 
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  • #2


No, no one on the outside can see your internal IP addresses. This is because your connectivity device (in this case a router) performs network address translation (NAT). This modifies the header of the packet and inserts the IP address of the router (the public address). The private address class (example 192.168.x.x) is not routable across internet. All outsiders will see is the public address assigned to you by your ISP. They can't know the internal setup unless you volunteer this info.
 
  • #3


Well, there are ways to guess that you are running behind a router. For example, nmap -O will try to guess the operating system, which will often say something like "Linksys embedded" for a router (assuming your router is visible to the internet, as it would be if you enabled remote administration). This page goes into detail about exactly how nmap makes that guess.
 
  • #4


what about this site?
http://www.auditmypc.com/anonymous-surfing.asp

(under the map it tells you your internal IP)

it uses a javascript silently, which doesn't only display your internal IP address to you, it also registers it in a list on that site.

is it possible my ISP's DNS redirects me first to a site like this one, runs the script, and then sends me off to wherever i wanted to surf?

maybe i'll do a traceroute just out of curiosity...
 
  • #5


No, your router uses NAT (Network Address Translation) to convert the internal to external IPs

j
 

Related to ISP can tell what my internal network ip's are?

1. How does my ISP know my internal network IP addresses?

When your device connects to the internet, it is assigned a public IP address by your ISP. This public IP address is used to communicate with other devices on the internet. However, within your internal network, your devices have private IP addresses that are not visible to the rest of the internet. Your router acts as a gateway between your internal network and the internet, and it translates your private IP addresses to your public IP address. This translation process allows your ISP to see your internal network IP addresses.

2. Can my ISP see all the devices connected to my internal network?

No, your ISP can only see the devices that are communicating with the internet. Your router acts as a barrier between your internal network and the internet, so your ISP cannot see the devices that are not connected to the internet.

3. What information can my ISP gather from my internal network IP addresses?

Your ISP can only see the IP addresses and the amount of data that is being transmitted to and from your internal network. They cannot see the specific websites or content that you are accessing within your network.

4. Can I prevent my ISP from seeing my internal network IP addresses?

No, it is not possible to hide your internal network IP addresses from your ISP. However, you can use a virtual private network (VPN) to encrypt your internet traffic and prevent your ISP from seeing the contents of your network.

5. Is it safe for my ISP to know my internal network IP addresses?

Yes, it is generally safe for your ISP to know your internal network IP addresses. They do not have access to the devices within your network, and the information they can gather is limited. However, it is always recommended to take additional precautions, such as using a firewall and keeping your devices and network security up to date, to protect your internal network from potential threats.

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