55531Re: [linux] Re: Whatever happened to "Linux Magazine"?
- Apr 2, 2009-----BEGIN PGP SIGNED MESSAGE-----
On 02/04/09 14:48, Harold Williams wrote:
> At the risk of looking really dumb...Could someone explain what using
> /etc/hosts means?
/etc/hosts contains the IP addresses of domain names. The resolver goes
through it when looking to resolve a domain name before asking DNS.
Therefore, if you have a line stating that, for example, ads.doubleclick.net
is on IP address 127.0.0.1, your browser will use that address and redirect
requests for that host to localhost instead of looking up the domain via DNS.
It's a quick and dirty way of making ads hosted on domains "redirected" this
way impossible for your browser to find and therefore display, but it does
have two drawbacks:
1) You need to have a line for every subdomain under a domain that you want
to conceal. So, if you want to conceal, say, host1.exmple.net,
host2.example.net all the way through host1000.example.net, you'd need to
add 1000 such lines to /etc/hosts.
2) It causes your networking subsystem to waste time trying to open a
connection on your own machine.
The DNS method is preferable because:
1) You can make the whole "example.net" domain disappear in one go with one
simple directive in your local nameserver's configuration file.
2) Domains concealed in this way really do disappear. The resolver is fed
information that the hostname you're trying to resolve simply doesn't exist.
No attempt to open a connection on your machine will take place.
G. Stewart - grs.ygroups@...
The quickest way to double your money is to fold it in half and put it
back in your pocket.
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