I found myself looking at a stock and forex search page when I try to access Chinese Stackexchange using my FireFox browser today. This is what the page looks like:

enter image description here

And this is the HTML of the page:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN" "http://www.w3.org/TR/html4/frameset.dtd">
<!-- turing_cluster_prod -->
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

    <meta name="keywords" content="stackexchange.com" />
    <meta name="description" content="stackexchange.com" />
    <meta name="robots" content="index, follow" />
    <meta name="revisit-after" content="10" />

    <meta name="viewport" content="width=device-width, initial-scale=1.0" /> 

    <script type="text/javascript">
      document.cookie = "jsc=1";

  <frameset rows="100%,*" frameborder="no" border="0" framespacing="0">
    <frame src="http://chinese.stackexchange.com?epl=someverylongstring" name="stackexchange.com">
    <body><a href="http://chinese.stackexchange.com?epl=thesameverylongstring">Click here to go to stackexchange.com</a>.</body>

Though rare, this is is not the first time I have encountered such a problem. My Google Chrome browser works correctly. And I suspect this has to do with my ISP's DNS. I immediately called my service provider notifying that there could be an issue with their DNS.

I tried surfing Stackexchange again and the issue is gone. Is it possible to confirm the source of the problem from my end? What others steps should I take to protect myself?

  • Carefully scan your computer for malware. Also, inspect your router to see if there are any peculiar DNS server entries.
    – Anorov
    Dec 21 '13 at 8:22

Without more information, the problem is very likely DNS related.

[ayrx@c00kies ~]$ host chinese.stackexchange.com
chinese.stackexchange.com has address

There are a few likely causes.

  1. A problem with your ISP's DNS. This is very a possible scenario that might stem from some bad configurations. If this is the case, switching to another DNS service provider like Google's might resolve the problem.

  2. Someone is conducting a MITM on your network. I'll say this is a less likely scenario as you probably are not a high value target and Stackexchange is not a high value site.

  3. You have malware messing with your machine's DNS to redirect you to that particular site. This is very possible as well. If this is the case, you can check by using another (hopefully clean) machine to access the Internet through your network. If this is the case, your best bet would be to nuke the infected machine and reinstall from scratch as cleaning up malware is very difficult.

  • Thanks for your help. It is actually a DNS issue with Firefox browser. See my answer below. Dec 21 '13 at 15:21

This is a self answer. I am documenting it here in case anyone came across the across the same issue.

After some researching, I realize this is a firefox browser DNS resolution issue due to some conflict with ipv6 though I am not using it. My problem disappears after toggling network.dns.disableIPv6 to true in about:config as per recommendation by Firefox (I am also facing a sluggish connection issue). I am able to replicate the problem by toggling the setting back to default.

Firefox browser somehow appends .com to the original url, leading to this search page. Under the link why am I here, it says:

Why am I here?

You likely reached com.com or a subdomain of com.com because (1) You or your internet browser appended an extra “.com” in the address bar of your internet browser, or (2) a link that you followed contained an extra “.com” in the web address. A subdomain is a domain name that is part of a larger domain. For example, com.com is the larger domain and one subdomain of com.com is ‘example.com.com’.

How do I get where I want to go?

If you got here by manually typing a web address into your browser’s address bar, there is a good chance that you can get where you wanted to go by removing the final “.com” from the web address you typed in. You may have noticed that third-party advertisers may have provided a number of links and advertisements relevant to the subdomain of Com.com that you attempted to reach. You may find these links and ads helpful to find what you’re looking for.

  • That doesn't explain why your screenshot showed chinese.stackexchange.com and not chinese.stackexchange.com.com, as I would expect Firefox to do if it appended a .com
    – Ángel
    Jul 16 '14 at 22:07
  • 1
    @Ángel, the extra .com is appended during DNS resolution, so you wouldn't see it on the address bar. Jul 17 '14 at 3:07
  • if Firefox added that .com, it can (and shall) update the address bar. If it was done by a dns resolver, it's broken (but AFAIK services "fixing" dns replies, like dnsadvantage, use a fixed server handling the queries, which is much less broken)
    – Ángel
    Jul 17 '14 at 19:21
  • @Ángel, its happens to Firefox, but not on Chrome and on two separate computers. So, I have to assume that it is a browser issue. Jul 18 '14 at 3:10
  • I thought it was on an old version. If you can reproduce it with a current version I would open mozilla a bug.
    – Ángel
    Jul 18 '14 at 20:18

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