While working on math, I encountered a number and wondered if it had any significance. So, in the browser search bar I entered it ("0.693"). I got redirected to the IP address, which resulted in an "unreachable" error message.

Why did I get redirected to this IP address?

  • 6
    ln(2) at first sight. – YSC Sep 18 '17 at 14:39
  • Are you sure you entered it in a search bar and not an address bar? – David Schwartz Sep 18 '17 at 16:57

Why did I get redirected to this IP address?

The browser address bar sees a . and thinks it is an IP address.

This gets passed to Windows to do a DNS lookup:

> nslookup 0.693
Server:  UnKnown

Name:    0.693


693 = 256 * 2 + 181

So 0.693 gets translated to

How can I prevent this conversion?

Prefix the value with '.

Enter image description here

| improve this answer | |
  • 8
    Also, many browsers have an actual search bar next to the address bar. Typing the search in there works as well. And there are also browsers who can search by typing g search phrase in the addressbar, such as Opera, Vivaldi and other chromebased browsers. – LPChip Sep 17 '17 at 21:37
  • 1
    @LPChip Yes. My FF is configured with a combined search/url bar (field). I had to enter http://0.693 to reproduce. – DavidPostill Sep 17 '17 at 21:38
  • 1
    I might be mistaken, but it seems to be because it has a dot so it is identified as url which goes to dns lookup, and for some reason Windows is happy to resolve it as ip address. – PTwr Sep 17 '17 at 21:40
  • @LPChip you can also assign keywords in FF like that. I always use a separate search box so I'll just need Ctrl+L for entering addresses and Ctrl+K for searching – phuclv Sep 18 '17 at 5:54
  • 9
    Prefixing with ? usually starts a search and prevents all further processing. In your case, when you prefix with ' you get a search term that contains the apostrophe. – Joey Sep 18 '17 at 6:57

The reason 0.693 becomes has been explained by DavidPostill. In short, the string looks like a valid IP address

Now to search for any terms use Ctrl+K (works in Firefox and Chrome) or Ctrl+E (only in Firefox). That'll trigger a search instead of letting the browser to guess if that's a valid address or not

| improve this answer | |

DavidPostill explained why you got redirected but didn't touch on how the number changed from 0.693 to

What's going on here is that while IP addresses are normally described as <number>.<number>.<number>.<number> they are really just 32 bit unsigned values, the dot notation is for convenience and really is just the value split into 4 8-bit groups separated with dots. While input normally is in the 4 group notion the parsers always accept it as a number.

693 = 256 * 2 + 181.

| improve this answer | |

Not the answer you're looking for? Browse other questions tagged or ask your own question.