Cannot modify '/etc/hosts' as administrator

Question

Level 1

9 points

Cannot modify '/etc/hosts' as administrator

Hi all,

I know there're a lot of discussions and solutions to this question, but my case is very strange. I have tried all the methods I've seen on the internet, including

sudo nano /private/etc/hosts
sudo vi /private/etc/hosts
sudo /Applications/TextEdit.app/Contents/MacOS/TextEdit /etc/hosts (I encountered an error by running this command: TextEdit[5872:3e07] NSTrackPersistentURLs: LSSharedFileListInsertItemURL() failed at inserting URL file://localhost/private/etc/hosts (/private/etc/hosts) )
Manually change permissions of private and etc foloder through Finder
Use the system preference pane 'Hosts'
Use Gas Mask

All methods I used above have problem overwriting the file (1, 2 said my hosts file is read only and I'm not permitted to overwrite, 5,6 didn't make a change on hosts file after I edited and saved). The account I'm using is an admin account, so I should have the permission to overwrite the hosts file. I used to be able to edit the hosts file and this problem only comes out early this year. I doubt if my hosts file is somehow damaged? Has someone here experienced it and is able to help me figure it out? I would really appreciate it.

Mac Pro, Mac OS X (10.7.5)

Posted on Nov 27, 2012 6:52 PM

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Answer 1

baltwo

Level 9

62,362 points

Nov 27, 2012 11:43 PM in response to hakerjack

Simplest is to copy the current hosts file to something like host.bak, then drag a copy to the Desktop. Open it in TextEdit, make the changes you want to make to it, save it as plain text, retaining the name hosts. Then, change its permissions with this command:

sudo chown root:wheel "path to file"?hosts

and then run this command:

sudo cp "path to file"/hosts /private/etc/hosts

Restart and your revised hosts file should be in play.

More info in http://hints.macworld.com/article.php?story=20100423134359860

Also, check the More like this box on this page.

FWIW, this is what the original looks like:

##

# Host Database

#

# localhost is used to configure the loopback interface

# when the system is booting. Do not change this entry.

##

127.0.0.1 localhost

255.255.255.255 broadcasthost

::1 localhost

fe80::1%lo0 localhost

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Answer 2

BobHarris

Level 9

53,003 points

Nov 28, 2012 5:59 AM in response to hakerjack

You should NOT change the permissions on /private and /private/etc. I suggest you run Disk Utility Repair Permissions and hope that it restores the permissions to what they should be. This is what the permissions should be:

/bin/ls -ldeo@ /private /private/etc

drwxr-xr-x@ 6 root wheel hidden 204 Oct 8 2011 /private

com.apple.FinderInfo 32

drwxr-xr-x 104 root wheel - 3536 Nov 22 13:09 /private/etc

"sudo nano /private/etc/hosts" should have worked, as well as the sudo vi command. Can you explain why it did not, as that might indicate either a simple misunderstanding, or an underlying problem.

And finally, can you explain why you think you need to change the 'hosts' file? Maybe there is a better alternative.

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Answer 3

baltwo

Level 9

62,362 points

Nov 28, 2012 9:45 AM in response to baltwo

Update to correct fat-fingering error:

sudo chown root:wheel "path to file"?hosts

should read

sudo chown root:wheel "path to file"/hosts

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Answer 4

red_menace

Level 6

17,030 points

Nov 28, 2012 10:07 AM in response to hakerjack

I've always used BBEdit or TextWrangler to edit the hosts file, since they take care of things such as navigating to those normally invisible places, line endings, etc, and will prompt for authorization.

By the way, an admin account does not automatically have access to everything (the hosts file is ownwed by root).

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Answer 5

Nov 28, 2012 2:35 PM in response to hakerjack

This is how I do it.

1 - drag /etc/hosts file to Desktop - with normal permissions this will result in a copy on the Desktop

2 - edit with BBEdit Lite - or any other clean text editor

3 - drag edited version to /etc folder

4 - agree to Authenticate and then Replace - admin password is required for this

5 - Restart to use modified hosts file.

Good luck

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Answer 6

baltwo

Level 9

62,362 points

Nov 28, 2012 3:20 PM in response to Neville Hillyer

Normally, dragging it to the Desktop changes the file's ownership to you; thus, my recommendation to restore the appropriate ownership and group permissions.

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Answer 7

Nov 29, 2012 2:22 AM in response to baltwo

It does change it to read/write for myself and read only for everybody else but this does not do any harm.

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Answer 8

Linc Davis

Level 10

209,541 points

Nov 29, 2012 5:37 PM in response to hakerjack

Please post the output of the following command:

ls -Odel /private/etc; ls -Oel $_/hosts

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Answer 9

Nov 30, 2012 4:17 AM in response to Linc Davis

I realise this was not a reply to me but I get:

drwxr-xr-x 90 root wheel - 3060 30 Nov 09:10 /private/etc

-rw-r--r--@ 1 neville staff - 582566 28 Nov 16:30 /private/etc/hosts

What do you conclude from this?

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Answer 10

hakerjack Author

Level 1

9 points

Nov 30, 2012 12:45 PM in response to BobHarris

Hi BobHarris,

I ran the Disk Utility Repair Permissions and it fixed some of the permissions I changed before. However, it didn't work. The hosts file is still read-only to me and do not let me to overwrite.

Thanks

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Answer 11

hakerjack Author

Level 1

9 points

Nov 30, 2012 12:46 PM in response to Linc Davis

Hi Linc,

This is what I got:

drwxr-xr-x+ 105 root wheel - 3570 Nov 27 18:44 /private/etc

0: group:admin allow list,add_file,search,add_subdirectory,delete_child,readattr,writeattr,readextat tr,writeextattr,readsecurity

-rw-r--r--@ 1 root wheel uchg 1051 Oct 3 2011 /private/etc/hosts

Kaiang-Jias-MacBook-Pro:~ KJ$ /bin/ls -Ideo@ /private /private/etc

What can you tell from these?

Thanks

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Answer 12

hakerjack Author

Level 1

9 points

Nov 30, 2012 1:07 PM in response to Neville Hillyer

Hi Neville,

I did that before but it didn't work. After read your comment I tried that again, and this time I paid attention to the error, so when I was trying to replace the file with original hosts file I get error:

The Finder can’t complete the operation because some data in “hosts” can’t be read or written.

(Error code -36)

Do you have any clue about that?

Thanks

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Answer 13

hakerjack Author

Level 1

9 points

Nov 30, 2012 1:13 PM in response to baltwo

Hi baltwo,

I tried your suggestion and after I typed sudo cp I got an error: cp: /private/etc/hosts: Operation not permitted.

Thanks

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Answer 14

Nov 30, 2012 1:23 PM in response to hakerjack

hakerjack wrote:

Do you have any clue about that?

Sorry - I don't - perhaps Bob or Linc can explain why it works for me on Leopard but not for your later OS.

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Answer 15

red_menace

Level 6

17,030 points

Nov 30, 2012 1:46 PM in response to hakerjack

I don't know how you got that ACL on the /etc folder, but your hosts file is locked (that uchg is the user immutable flag). Only the owner or root can change that flag (the owner in this case is root), so as an admin user you can use sudo:

sudo chflags nouchg private/etc/hosts

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