The hosts file on windows computers is used to bind certain name strings to specific ip addresses to override other name-resolution methods
Sometimes one decides to change the hosts file and discovers that the changes refuse to take effect or that even old entries in the hosts file are ignored thereafter There are a number of mistakes that can cause this and it can be frustrating to figure which one to blame
What's the best troubleshooting procedure for windows ignoring a hosts file?
This question has duplicates on SO, such as HOSTS file being ignored
These tend to deal with a specific case but once any mistake made by the op is discovered the discussion is over If you have not made the same error this discussion isn't very useful So I thought it would be more helpful to have a general protocol for resolving all hosts-related issues that would cover all cases.
Based on my own experience and what i encountered when googling here are some things i should try
1. Did you check that it works correctly?
The changes to hosts should take effect immediately but windows caches name resolution data so that they may be used for some time Open a command line (Windows+R,
cmd , Enter) and type.
To remove the old data To check if it works, use (assuming you have an ipv4 entry in your hosts for www.example.com , or an ipv6 entry in your hosts for ipv6.example.com).
ping www.example.com -n 1 ping -6 ipv6.example.com -n 1
So you'll see if it uses the correct ip If yes, your hosts file is fine and the problem is elsewhere.
Also, you can reset the netbios cache with (open the console as an admin or it will fail).
You can check the data in the current dns cache
ipconfig /displaydns | more
nslookup does not look at the hosts file. See NSLOOKUP and NBLOOKUP give one IP address; PING finds another
- Should my host file be named correctly? It should be
- Is this extension correct? It should have no extension (
hosts.txt) - be careful if you have configured windows to hide known extensions, check the properties to be sure: The correct hosts file's type will show up as just "File".
- Did you follow the correct syntax ? Did you accidentally prefix lines with a hash (
#) which indicates comments?
- Did you take care of all variants (
example.com- safest to just add both)?
The format for each line is
IP address , then a horizontal tab (escape code
\t , ASCII
HT , hex
0x09 ) or a single space (hex
0x20 ), then the host name, ie.
www.example.com , then finally a carriage return followed by a line feed, (escape codes
\r\n , ASCII
CRLF , hex
0x0d 0x0a ).
Examples of entries using unicode control pictures to indicate control characters (Don't copy and paste these into your hosts file!)
The individual bytes may be viewed in Notepad++ with the hex editor plugin . Notepad++ will also show special characters (view -> show symbol) so you can easily inspect the number and kind of whitespace characters.
If you copy and pasted host entries from somewhere you may end up with multiple spaces In theory hosts supports multiple spaces separating the two columns, but it's another thing to try if nothing else works.
To be on the safe side, make sure all lines in your hosts file either use tabs or spaces, not both.
End the file with a blank line
4. Registry Key
There's a registry key specifying the location of the hosts file Windows doesn't support the option to set hosts in other files but you might want to check The key is
The entry should be.
Sometimes there are issues with permissions on the file, the file attributes, and similar things. To recreate the file with default permissions.
- Create a new text file on your desktop
- Copy and paste the contents of your current hosts file into this file in notepad
- Save the new text file and rename it to
- Copy ( do not move ) the file to your
%SystemRoot%\System32\drivers\etcdirectory, and overwrite the old file.
Last point is important: copying works, moving doesn't.
Users account must be able to read the hosts file . To make sure (in windows 7).
- Navigate to
%SystemRoot%\System32\drivers\etcin Windows Explorer.
- If you can't see the
hostsfile, ensure you can see hidden and system files .
- Right-click on the
hostsfile and select
Propertiesfrom the context menu.
- In the
hosts Propertieswindow, click on the
- Examine the list of names in the
Group or user names:box. If
%COMPUTERNAME%\Usersis present, click on it to view permissions.
Usersis not present, or is present but does not have
Usersis not present, click
Check Names, and click OK or press Enter.
Users, and ensure
Read & executeis checked in the
Allowcolumn. Click ok. If a
Windows Securityalert box pops up, choose
- Click OK to close the
- Go to section 1 of this answer and follow the instructions to check if it's working
The hosts file should be encoded without bom in ansi or utf-8 You can do this by selecting file - save as
If you have a proxy configured it might bypass the hosts file The solution is to not use the proxy or configure it to not do this
To check, go to your internet explorer -> internet options -> connections -> lan settings. If everything is blank and "automatically detect settings" is checked, you aren't using a proxy.
If you rely on a proxy to access the web and you don't want to disable it you can add exceptions to internet explorer - internet options - connections - lan settings - proxy server advanced Then add your exceptions to the text box exceptions e.g.
8. DNS address
(This may also resolve proxy issues.)
Go to your network connections properties, then TCP/IP settings, and change the first DNS server to
127.0.0.1 (localhost). The second should probably be your actual ip address in your dns system
This is not necessary for the hosts file to work , but it may help in your case if something is configured strangely.
9. .local addresses
If you are using a .local domain entry in the form of myhost.local and it gets ignored please try the following.
x.x.x.x myhost.local www.myhost.local
even if the www.myhost.local does not exist. Windows does not append its workgroup or localdomain
10. Line / count limits
(added to this answer to make it visible as it's been mentioned a few times)
A windows host file appears to have a line or limit If you have more than 150 characters on a line or more than 8 hosts entries for an IP create a new line
e.g. instead of.
18.104.22.168 host1.com host2.com host3.com host4.com host5.com host6.com host7.com host8.com host9.com
22.214.171.124 host1.com host2.com host3.com host4.com host5.com 126.96.36.199 host6.com host7.com host8.com host9.com