4 ms·

Can you explain the reasoning behind using 0.0.0.0 instead of 127.0.0.1? Genuinely interested.

sergiotapia 11y ago
Basically it's slower if you use 127 because it actually checks if something is running (example a server or whatever). 0.0.0.0 means explicitly "there is zilch, nip, nada". It's a little bit faster.
- jakeogh 11y ago
  NXDOMAIN is also an option if you use dnsmasq. I havent tested if 0.0.0.0 actually returns NXDOMAIN, but from you comment, it sounds like yes. Also see --dest-ip in "dnsgate config --help".
- ciupicri 11y ago
  telnet 0.0.0.0 $port works fine on my machine, it connects to localhost, so besides the speed, I don't think there's any other difference at least on Linux.
  - lisivka 11y ago
    "ssh 0" or "ssh ::" works fine too. Also "http://0" http://0" or "http:// http://[::]".
- laumars 11y ago
  You can have processes listen on 0 - which means all available IPv4 IPs (available to that machine). And since you can have processes listen on 0, it means you can equally curl 0; just like you could with 127.0.0.1. Here's an example from my IRC server (the only process I run on 0): $ curl https://0:9997 -kis | head HTTP/1.1 200 OK Date: Fri, 12 Feb 2016 07:49:24 GMT Server: ZNC - http://znc.in Content-Length: 1878 Content-Type: text/html Set-Cookie: 9997-SessionId=54245f15ba592bc691e09ac75e6778e6d4c33841fad71a8d6c56addc998e043f; path=/; Connection: Close <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> (just in case someone queries, 0 is just another notation of 0.0.0.0)
Goopplesoft 11y ago
Its in the repo's readme: https://github.com/StevenBlack/hosts#why-use-0000-instead-of-127001 https://github.com/StevenBlack/hosts#why-use-0000-instead-of...
singlow 11y ago
I do some blocking with my hosts file, and I used to put 127.0.0.1. That hits my default nginx vhost, so i usually get 404 or 403 pages which is not so bad since my default vhost is an empty docroot. But it is not very intuitive and sometimes I think a server is down because of the nginx error page before I realize its my hosts file. I considered making a custom error message for my default host to remind me what I'm hitting, but I'm lazy.
jeswin 11y ago
Security. I suppose it would be possible to craft a url that attacks local web services sometimes found on developer machines. If someone can confirm this is indeed the case, I'll submit a pull request to their README.
- nes350 11y ago
  This won't work, at least on Chrome. It blocks all cross-domain requests to localhost[1]. Even if the target is used with a domain that resolves to 127.0.0.1, or has CORS completely disabled with "Access-Control-Allow-Origin: *". [1] https://code.google.com/p/chromium/issues/detail?id=67743 https://code.google.com/p/chromium/issues/detail?id=67743

Basically it's slower if you use 127 because it actually checks if something is running (example a server or whatever). 0.0.0.0 means explicitly "there is zilch, nip, nada". It's a little bit faster.

jakeogh 11y ago
NXDOMAIN is also an option if you use dnsmasq. I havent tested if 0.0.0.0 actually returns NXDOMAIN, but from you comment, it sounds like yes. Also see --dest-ip in "dnsgate config --help".
ciupicri 11y ago
telnet 0.0.0.0 $port works fine on my machine, it connects to localhost, so besides the speed, I don't think there's any other difference at least on Linux.
- lisivka 11y ago
  "ssh 0" or "ssh ::" works fine too. Also "http://0" http://0" or "http:// http://[::]".
laumars 11y ago
You can have processes listen on 0 - which means all available IPv4 IPs (available to that machine). And since you can have processes listen on 0, it means you can equally curl 0; just like you could with 127.0.0.1. Here's an example from my IRC server (the only process I run on 0): $ curl https://0:9997 -kis | head HTTP/1.1 200 OK Date: Fri, 12 Feb 2016 07:49:24 GMT Server: ZNC - http://znc.in Content-Length: 1878 Content-Type: text/html Set-Cookie: 9997-SessionId=54245f15ba592bc691e09ac75e6778e6d4c33841fad71a8d6c56addc998e043f; path=/; Connection: Close <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> (just in case someone queries, 0 is just another notation of 0.0.0.0)

Goopplesoft 11y ago

Its in the repo's readme: https://github.com/StevenBlack/hosts#why-use-0000-instead-of-127001 https://github.com/StevenBlack/hosts#why-use-0000-instead-of...

singlow 11y ago

I do some blocking with my hosts file, and I used to put 127.0.0.1. That hits my default nginx vhost, so i usually get 404 or 403 pages which is not so bad since my default vhost is an empty docroot. But it is not very intuitive and sometimes I think a server is down because of the nginx error page before I realize its my hosts file. I considered making a custom error message for my default host to remind me what I'm hitting, but I'm lazy.

jeswin 11y ago

Security. I suppose it would be possible to craft a url that attacks local web services sometimes found on developer machines. If someone can confirm this is indeed the case, I'll submit a pull request to their README.

nes350 11y ago
This won't work, at least on Chrome. It blocks all cross-domain requests to localhost[1]. Even if the target is used with a domain that resolves to 127.0.0.1, or has CORS completely disabled with "Access-Control-Allow-Origin: *". [1] https://code.google.com/p/chromium/issues/detail?id=67743 https://code.google.com/p/chromium/issues/detail?id=67743