tobe said:
In Advanced tools/system Explorers/Networking there is a
Windows Hosts file, which shows a long list of sites
which are apparrently looped back to the local host
address 127.0.0.1. There are options to 'block
host', 'unblock host', and 'permanently remove host' for
each individual host. It appears that each host
is 'unblocked' by default.
What does it mean to block, unblock, or remove any
particular host on this screen? Which option provides
protection from the host (i.e. redirects it to the looped
back site instead of the actual host site)? The Help
section on this is useless.
I agree--this help is not helpful.
By default, the hosts file has only a single active entry--127.0.0.1
localhost.
Your hosts file has been modified by one (or more!) third-party programs,
viruses, or spyware, to include lines which will cause various listed
domains to resolve to localhost (i.e. fail to be reached.)
As long as all those domains are ones you don't want to reach, you can leave
that alone--I know this begs the question of the meaning of the choices in
Microsoft Antispyware---I'll test that in a minute.
The problem with such a long list of hosts is that both the bad guys and the
good guys use this list--for opposing purposes. A number of viruses and
trojans add popular commercial antivirus vendors sites to the hosts file.
So--to be sure of what is happening, you need to examine every entry in that
file and satisfy yourself that they are all ones you wish to avoid visiting.
Thats why my hosts file has only the default single entry.
The hosts file is a simple text file located in
\windows\system32\drivers\etc
Its name is hosts with no suffix. It can be edited in notepad.
OK - I've added an entry 127.0.0.1
www.largeuniversitynearme.edu
Blue alert: A Windows hosts file change requires your approval
The hosts file can set which Web site your browser visits when you type a
URL in the address bar. This change occurs in limited circumstances. You
should block this change if you have not made the change or run a program to
do so.
Host:
www.microsoft.com
IP Address: oft.com|127.0.0.1
Now, when I do ping
www.largeuniversitynearme.edu, it goes to 127.0.0.1
If I try to open that URL in a browser, I get a 401.1 error.
So--host blocking is working, now what about Microsoft Antispyware?
The only valid (i.e. ungreyed out) choice is Block Host. So I "block host"
for
www.largeuniversitynearme.edu.
And, at this point, pings and web access proceed to the correct public IP
address, and it all works.
So--the meaning of BLOCK HOST appears to be "remove this entry from the
hosts file."
In fact, when I look at the hosts file, the entries I have blocked are
commented out, with a # sign at the start of the line.
For extra credit--I'd be interested in hearing from someone who can explain
why putting
www.microsoft.com or microsoft.com in such a line fails to have
the same effect--I'm intrigued--I don't know whether it is something
intentionally built into Windows DNS resolution, or a side-effect of the
load balancing mechanisms.
So--my preference, and that of a good many others, is to keep this file
near empty--just the default entry and anything necessary for work or
testing I'm engaged in. Opinions differ on this, and I concede that these
entries in a hosts file have probably saved much grief in families with
teenagers, say, over the years.
Does that help--or did I say too much?