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Noticed an interesting thing whilst debugging one of my websocket applications that Google Chrome will push out 3 http requests upon a network connection status changing;

Quite disconcerting and looks almost as if some malware is checking out to a random server.

I don't quite understand the why though since they all return a 502 or have no response code at all since the destination does not exist.

On Disconnect:

Connection Down

Reconnect:

Connection Up

I guess the main question is this normal and what the use is; howcome they wouldn't go for a dns lookup that actually exists?

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  • 1
    howcome they wouldn't go for a dns lookup that actually exists? Actually exists relative to who? Relative to my PC? zcpluzmxwt probably won't get anywhere. Relative to your malware-riddled box? zcpluzmxwt is probably in your hosts file. Apr 8 '12 at 9:37
  • @ta.speot.is nothing in there that looks anything like the above, like I said its only when chrome is running that these requests are seen. Apr 8 '12 at 9:42
  • thanks for the comment though, @ta.speot.is ; seems the worst is always the first option. Apr 8 '12 at 11:41
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As I remember, this is a special feature of Chrome. This feature is used to help to detect if your provider specially process invalid dns entries. chromium bugtracker - latest message

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  • :) thanks, seems like there were quite a few people with the same observation and theory. thanks again. Apr 8 '12 at 10:42
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It looks alarming but is apparently normal and intended behaviour in Chrome.

In order to use the address/location bar for searches and not just URLs, Chrome needs to check that the entered text isn't a valid domain before it can treat it as a search term. However, some IPSs serve advertising pages in response to non-existent domains (DNS Hijacking), which would make it appear that every domain exists! To test for this, Chrome will query some random, likely bogus single-word domains and see if they map to the same IP address. If they do, Chrome can assume that the upstream ISP is performing DNS hijacking.

See also Chrome: DNS requests with random DNS names: malware?, Chromium issue 47262

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  • Wouldn’t say it’s harmless. If they can redirect when you attempting to view a domain that doesn’t exist they can redirect you when a domain does exist
    – Ramhound
    Apr 17 '20 at 4:48
  • @Ramhound Certainly DNS hijacking in general is far from harmless, but the original question seemed to be asking specifically about Chrome's unusual behaviour. I'll see if I can reword the answer better.
    – screwtop
    Apr 20 '20 at 5:52

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