There is this one website that won't let me connect from my PCs connected to the same router. I tried turning off the router, wait 15 minutes, restart it to make sure it gets a different ip address from my ISP. I also tried TOR browser and ZenMate chrome extension that ensures my traffic goes through one of their servers but the site still rejects me. I tried it using firefox, chrome and IE in privacy modes. also tried clearning all history (cache, tracking info).

I know the site is up and running because when i connect to it from my smartphone using cellular network i am able to see contents.

How could this site still know it is me?


  • I checked my ipaddress at whatismyipaddress.com or similar site after using TOR or ZenMate and the site shows expected ip address: different from mine in different country.
  • Since using TOr or ZenMate fail as well i don't think it is ip address based detection.
  • after failing to connect to the site on my laptop, i went to my pc that never accessed the site before and it won't connect either.
  • Do you get the same issue if you're using your smartphone as a tether to the cellular network?
    – Jenny D
    Jan 5, 2015 at 9:46
  • What does happen when you use a "blocked" PC?
    – Bob Brown
    Jan 5, 2015 at 11:22
  • What happen if you enable wifi-hotspot on your phone, and connect with your laptop through it? Jan 5, 2015 at 11:32
  • Hm.. that was interesting. I enabled wifi on my phone and wasn't able to connect either. It appears that they are using ip address based detection. I understand why TOR doesn't work (myipaddress site shows that i am using some sort of proxy) but not sure why ZenMate won't (myipaddress doesn't show i am using proxy)
    – user64694
    Jan 5, 2015 at 14:43
  • Could you tell which site this is?
    – qbi
    Jan 6, 2015 at 7:19

5 Answers 5


It probably blocks an entire IP range because of abuse. So if you get another IP address, it probably is still in the same range, like 12.34.56.xx. In that case it doesn't matter if xx=3 or xx=123. If you use another computer on the same local network (like smartphone with wifi or VM with different OS), and still have this problem, that means they block the range.

Your use of TOR may be seen as abuse. I've had this myself. I had a TOR node installed on a home server. The result was that I was blocked on one discussion forum. I mailed them about it because the site was totally blank at home, while it worked elsewhere. They said my IP was blacklisted because of TOR. And this was a normal TOR node, not an exit node! I told them this and they (an IT site) acknowledged it as being a wrong block, but couldn't remove my IP from the blacklist.

Another option is that they identify the computer using CSS and Javascript. There are several options like checking screen size and which fonts you have installed. This is probably enough to uniquely identify your computer.

  • If it blocks the OP even when they're connecting through TOR, it's unlikely to be the ISP's IP range that's the issue. Of course, they may be blocking known TOR exit nodes as well.
    – Jenny D
    Jan 5, 2015 at 9:45
  • Using TOR is a possible cause. See my edited answer.
    – SPRBRN
    Jan 5, 2015 at 10:00
  • 1
    If you are blocking IP ranges for abuse, blocking TOR seems to go right along side it. Jan 5, 2015 at 14:55

One thing to do is check your DNS configuration. It's possible you have malware that has hijacked your DNS so one machine can resolve it fine whereas the other does not.


Are you sure your "External" ip address changed? most of the time this does not change even if you switch the router on/off. and its possible your IP is blacklisted in there firewall for abuse or other use (or someone that had your IP before you did that) if that's the case, contact them through other means and ask them for assistance.

Also, there are several ways of identifying you, through an image in your "cache" through the properties of your system (like fonts available and many more parameters) and if there really good through cryptographic authentication of your browser (although a different browser would than work) and its possible your IP gets blacklisted as soon as you contact that site with a browser they can identify (and have marked as abusive)

  • Thank you for your answer but i edited my question: "after failing to connect to the site on my laptop, i went to my pc that never accessed the site before and it won't connect either. the pc is in the same router"
    – user64694
    Jan 5, 2015 at 14:38
  • your still assuming they have not already blocked known TOR exit node's / VPN's and that your IP has in fact changed. the only way to get more answers (without experienced network debugging) is ASKING the website operators whats going on. not asking it on stackexchange.
    – LvB
    Jan 5, 2015 at 16:14

From the outside looking in we cannot know what they're doing. My first guess is zombie cookies. There are many ways of identifying a particular machine, or even a particular user, besides IP address and HTTP cookies. Marketers, particularly, want to know who we are even f we clear cookies, so they're continually probing for ways to hide persistent data on our computers.

You could try borrowing a laptop and connecting with the laptop, but from your own router after renewing the IP address. If the laptop connects, there is some type of persistent storage on the PCs you've been using.

Based on the fact that you've seen the same effect with different browsers and after clearing the cache, my guess, and it's only a guess, is that Flash local storage is being used.

  • Thank you for your answer but i edited my question: "after failing to connect to the site on my laptop, i went to my pc that never accessed the site before and it won't connect either. the pc is in the same router"
    – user64694
    Jan 5, 2015 at 14:39
  • Try the PC after you force the router to get a new IP address.
    – Bob Brown
    Jan 5, 2015 at 17:31

You said that you can access the site from a mobile phone. This may indicate that the site is storing a mark in your browser. See http://samy.pl/evercookie/ : "extremely persistent cookies in a browser". "Evercookie" can recreate itself between browsers in certain cases, outlined in its documentation.

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