/etc/hosts file not being used in Snow Leopard

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Level 1

60 points

/etc/hosts file not being used in Snow Leopard

I have added several hosts to my /etc/hosts file in Snow Leopard. In Leopard (10.5), once I saved the /etc/hosts file, the hosts were available and usable. In Snow Leopard, it's like this file is never read or used. I cannot get Snow Leopard to use these entries at all in Terminal. I use this "local DNS" style feature every day at work to connect to computer systems on the corporate LAN.

In past releases, you had to import these entries into NetInfo; however, as of Leopard, my understanding is that NetInfo is gone (or, at least, niload is).

Am I missing a new step in Snow Leopard? I have tried logging out and back in, and I've restarted the computer many times since the entries were made.

Any help would be much appreciated.

MacBook Pro Core 2 Duo, 2.66GHz, 4GB RAM, 320GB HDD, Mac OS X (10.6.1)

Posted on Sep 16, 2009 10:24 AM

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Answer 1

Top-ranking reply

V.K.

Level 9

56,174 points

Sep 16, 2009 10:33 AM in response to Sharp-man

/etc/hosts works fine in snow leopard. make sure you use the correct syntax when editing it and also make sure that it has correct permissions. it should be owned by the system and have 644 permissions.

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Answer 2

Sharp-man Author

Level 1

60 points

Sep 16, 2009 11:57 AM in response to V.K.

V.K. wrote:
/etc/hosts works fine in snow leopard. make sure you use the correct syntax when editing it and also make sure that it has correct permissions. it should be owned by the system and have 644 permissions.

Well, don't I feel stupid... I had switched the order of the entries to "name<tab>IP address" rather than "IP address<tab>name". 😟

Thanks for making me double-check. I only work in Unix every day... 🙂

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Answer 3

V.K.

Level 9

56,174 points

Sep 16, 2009 1:02 PM in response to Sharp-man

Sharp-man wrote:

V.K. wrote:
/etc/hosts works fine in snow leopard. make sure you use the correct syntax when editing it and also make sure that it has correct permissions. it should be owned by the system and have 644 permissions.

Well, don't I feel stupid... I had switched the order of the entries to "name<tab>IP address" rather than "IP address<tab>name". 😟

don't feel too bad. I for one also have to double-check the order of the fields in /etc/hosts every time I edit it (which is not very often).

Thanks for making me double-check. I only work in Unix every day... 🙂

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Answer 4

Tex-Twil

Level 1

6 points

Sep 28, 2009 12:57 PM in response to V.K.

Hello,
well I have the same problem even with the correct syntax. I put this inside:

127.0.0.1 facebook.com

but the name still gets resolved

~ $ host facebook.com
facebook.com has address 69.63.184.142
facebook.com has address 69.63.176.140
facebook.com mail is handled by 10 mx.sf2p.tfbnw.net.
facebook.com mail is handled by 10 mx.snc1.tfbnw.net.

Any ideas ?

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Answer 5

Dogcow-Moof

Level 8

36,557 points

Sep 28, 2009 8:12 PM in response to Tex-Twil

You need to flush the system DNS cache after adding the host to /etc/hosts or the system will use the last cached translation until it expires.

Either run the following in a Terminal window:

sudo dscacheutil -flushcache

Or logout of your account and log back in.

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Answer 6

Tex-Twil

Level 1

6 points

Sep 28, 2009 11:11 PM in response to Dogcow-Moof

Hi,
it doesn't work

~ $ sudo dscacheutil -flushcache
~ $ host facebook.com
facebook.com has address 69.63.176.140
facebook.com has address 69.63.184.142
facebook.com mail is handled by 10 mx.sf2p.tfbnw.net.
facebook.com mail is handled by 10 mx.snc1.tfbnw.net.

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Answer 7

Dogcow-Moof

Level 8

36,557 points

Sep 29, 2009 1:56 AM in response to Tex-Twil

Sorry, I didn't notice you were using the host command.

Utilities that directly use the DNS resolver like dig, host and nslookup never use local files.

But if you try to visit facebook.com with Safari, you won't be able to get there.

For example, try this after placing your entry in /etc/hosts:

dscacheutil -q host -a name facebook.com

From the man page for host(1):

Mac OS X NOTICE
The host command does not use the host name and address resolution or
the DNS query routing mechanisms used by other processes running on Mac
OS X. The results of name or address queries printed by host may
differ from those found by other processes that use the Mac OS X native
name and address resolution mechanisms. The results of DNS queries may
also differ from queries that use the Mac OS X DNS routing library.

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Answer 8

Tex-Twil

Level 1

6 points

Sep 29, 2009 9:33 AM in response to Dogcow-Moof

ok for the host command but Firefox and Safari still can resolve the IP.

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Answer 9

Dogcow-Moof

Level 8

36,557 points

Sep 29, 2009 12:12 PM in response to Tex-Twil

That shouldn't be the case.

If the dscacheutil query listed above can't resolve the host, neither Firefox nor Safari should be able to, either.

If the dscacheutil query still can resolve the host, you may have made an error adding your entry to /etc/hosts.

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Answer 10

Tex-Twil

Level 1

6 points

Sep 29, 2009 12:33 PM in response to Dogcow-Moof

$ dscacheutil -q host -a name facebook.com
name: facebook.com
ip_address: 127.0.0.1

When I open FF or Safari and type facebook.com it works ..

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Answer 11

Dogcow-Moof

Level 8

36,557 points

Sep 30, 2009 3:10 AM in response to Tex-Twil

I'm not sure how you're typing "facebook.com", but if I add this line to /etc/hosts:

<pre>127.0.0.1 facebook.com</pre>

then do a:

dscacheutil -flushcache

I can no longer reach facebook.com, getting an error stating Safari cannot contact facebook.com.

However, the problem is that after doing that you can still access www.facebook.com.

I'm also assuming you have "Configure IPv6" set to "off" in your network interface's "Advanced-TCP/IP" tab.

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Answer 12

Oct 5, 2009 6:19 PM in response to Dogcow-Moof

I'm having the exact same issue as Tex-Twil, but I'm kinda new to this so I'm not that great with the terminology. I've done pretty much everything you've said so far, but no luck. Oh, and this is on an Intel Mac Mini running 10.5.8.

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Answer 13

Oct 17, 2009 10:13 AM in response to Sharp-man

Don't think this issue is resolved...I'm having the same issues after adding to the host file. Safari seems to be able to resolve anything I put in that file. However, in FF the host file works.

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Answer 14

Dogcow-Moof

Level 8

36,557 points

Oct 17, 2009 1:19 PM in response to scorpio333

You have to both add the entry to the host file and flush the DNS cache with dscacheutil -flushcache.

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Answer 15

Oct 19, 2009 12:46 PM in response to Dogcow-Moof

Okay, so here's the odd part -> if I make the domain I'm trying to fool 127.0.0.1, it works as advertised. As soon as I try to make it some other address, it fails.

For example:

/etc/hosts
127.0.0.1 localhost somedomain.com

then

sudo dscacheutil -flushcache

Safari sees the /etc/hosts value.

/etc/hosts
192.168.1.99 somedomain.com

then

sudo dscacheutil -flushcache

Safari does not see the /etc/hosts value.

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