Unable to resolve host - problem!

[Tim Silver]

Hi,

I'm completely new to Ubuntu (only installed it this morning), so please forgive!

8.04 installed on external hard drive on Dell Inspiron 9400.

I was following the 'sticky' by kevdog but stumbled at first hurdle!

I typed 'lshw -C network' and got the details of both my wireless and ethernet interfaces - fine.

Then, 'sudo ifconfig wmaster0 down' gave the response - 'sudo: unable to resolve host tim-laptop'

Could someone point me to appropriate reading please. The only thing I can add is that I'm pretty sure it's not a hardware issue.

[chili555]

I'm pretty sure it's not hardware, either. Could you please post the result, in a terminal, of:cat /etc/hostsLet's see if we need to tweak it a bit.

[BightningLug]

I get the same "unable to resolve host" message.

Here's the results of cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 hog-dev.hog.dev

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

[chili555]

When you open a terminal, does it report the name of your computer as tim-laptop like mine does LAPTOP60?chili@LAPTOP60:~$My hosts file relates LAPTOP60 to 127.0.1.1.127.0.0.1 localhost
127.0.1.1 LAPTOP60

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhostsI suggest making a backup of your hosts file, just in case we err:sudo cp /etc/hosts /etc/hosts.bakThen I suggest sudo gedit /etc/hosts to amend it to:127.0.0.1 localhost
127.0.1.1 tim-laptop

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhostsSave and close gedit. Then restart networking:sudo /etc/init.d/networking restartThen let's see if your problems have been solved.

Any idea where: hog-dev.hog.dev came from?

[Tim Silver]

Hi Chilli,

Thanks for reply (sorry for delay but have to do this at work!)

tim@tim-laptop:-$ cat /etc/hosts
127.0.0.1 locahost
127.0.1.1 tim-laptop.PMS

#The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff03::3 ip6-allhosts
192.168.1.193 Tim Host
tim@tim-laptop:-$

The PMS will be the company network (I guess). I'm not trying to connect to the network - just to the router for internet access.

[mattress]

Howdy...

I think it may be a problem with the last entry in your hosts file:

192.168.1.193 Tim Host



Try changing that to something else or commenting it out with a #
Generally host entries are like so:


IP hostname alias
192.168.0.1 mymachine.mydomain.com mymachine


I could be wrong though...

[Tim Silver]

Hi mattress,

I'll try that but won't be able to do so for 3 hours (lunch-time in the UK). However, I think my problem may be more serious. When in a terminal, the cursor stops blinking, turns white (just borders showing) and freezes - I have to 'click' in the window to continue. I installed 8.04 from a live CD and have read (subsequently) that I should have performed a 'clean' install.

[Tim Silver]

mattress,

Before changing the 'hosts' file, I first went to make a backup of it (as suggested by Chili555). Here's the result -
tim@tim-laptop:-$ sudo cp /etc/hosts /etc/hosts.bak
sudo: unable to resolve host tim-laptop
tim@tim-laptop:-$

!!!!!!!!!!!!!!!!!!!

So what do I do now? I'm fully prepared to start from scratch but, of course, XP no longer sees my external drive so I can't format it. Any suggestions most welcome.

[jetsam]

This is a new kink in Hardy-- sudo fails if your hostname can't resolve.

You need to edit the file to function as per post 4, but since you can't sudo, you're stuck in a catch 22.

Two possible solutions:
try
gksudo gedit /etc/hosts
might work, and is easier. Several people have reported that gksudo works for them even when sudo fails. If you can get gedit running, you may be able to make a copy from gedit before you change the actual file.

The other possibility is to reboot into recovery mode. This will give you root access and allow you to copy the file and edit it with
nano /etc/hosts
or the terminal based text editor of your choice.

[Tim Silver]

Hi Jetsam,

gksudo gedit /etc/hosts - cursor just went to new line and did nothing.

I then booted into recovery mode (scary! well, it was my first time and I'm only 55::lolflag:), commented out the last line and saved.

Continued with normal boot, opened terminal and typed
sudo ifconfig wmaster0 down
still got the same
sudo: unable to resolve host tim-laptop

'Mattress' also suggested trying to change the 'hosts' file along the lines of
IP hostname alias
192.168.0.1 mymachine.mydomain.com mymachine
If I replaced <mymachine> with <tim-laptop>, where might I find the <mydomain.com> info?

[jetsam]

You can add secondary host definitions after the first one.

127.0.1.1 tim-laptop tim-laptop.PMS
...would resolve both tim-laptop and tim-laptop.pms to the local machine.

The important part, though, for sudo, is just the first part in bold above. You need to be able to resolve your hostname without the domain extension.

Are you sure you set this line correctly? I'm concerned that this isn't working.

[jetsam]

If you're still stuck, a status update might help with diagnosis. Can you post the output of:
cat /etc/hosts
cat /etc/nsswitch.conf
and
ping -c3 localhost
They really ought to change sudo back so this doesn't happen. A bunch of new users are getting caught up with this.

[diegomedaglia]

Hi! I just had this problem. You have to become a superuser to edit your /etc/hosts, but you've got to have your root password set.


go to System->Administration->Users and Groups
click on 'Unlock' and enter your administrator password (for some reason this authentication still works)
select user 'root' and click 'Properties'
in the fields below 'Set Password by hand' enter a new password (must be 6 characters long)

You should now be able to become superuser. Open a terminal and code:

su
gedit /etc/hosts

My problem was the line like "127.0.1.1 tim-laptop.PMS". I just removed the ".PMS" and it started working again. In my case I had
127.0.1.1 diego-ubuntu.WORKGROUP
Changing it to "127.0.1.1 diego-ubuntu" did the trick.

Hope this helps!

[Tim Silver]

Morning!

Right, jetsam, results:
cat /etc/hosts
returned
127.0.0.1 localhost
127.0.1.1 tim-laptop.PMS

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localhost
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff002::3 ip6-allhosts
#192.168.1.193 Tim Host
(Remember that you suggested I try commenting out the last line)

cat /etc/nsswitch.conf
returned (there was some commented out stuff that I haven't bothered typing as I'm guessing you already know what it says:lolflag:)
passwd: compat
group: compat
shadow: compat

hosts: files mdns4_minimal (NOTFOUND=return) dns mdns4
network: files

protocols: db files
services: db files
ethers: db files
rpc: db files

netgroup: nis

and
ping -c3 localhost
returned
PING localhost (127.0.0.1 56(84) bytes of data
64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl64 time=0.041 ms
64 bytes from localhost (127.0.0.1): icmp_seq=2 ttl64 time=0.040 ms
64 bytes from localhost (127.0.0.1): icmp_seq=3 ttl64 time=0.039 ms
--- localhost ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1998ms
rtt min/avg/max/mdev = 0.39/0.40/0.41/0/000 ms
(I think I copied all of that correctly)

I'm now going to remove the hash from the last line of hosts and try what diegomedaglia suggested. I'll keep you informed!

[jetsam]

OK. That's all good.

Make your file look like this:
127.0.0.1 localhost
127.0.1.1 tim-laptop tim-laptop.PMS

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localhost
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff002::3 ip6-allhosts
#192.168.1.193 Tim Host

Changes in red. You can leave the last line commented. I don't think it will do any harm either way, but I don't think it's necessary, either.

[Tim Silver]

Well, I've tried without the .PMS as per diegomedaglia and with the extra <tim-laptop> as per jetsam. (I must admit that it was a nicer experience editing through 'super user' method rather than in recovery mode - although it changed my keyboard settings to US!)

Sorry guys, but still no internet!

It's probably me. I'm working on the assumption that the heron will automatically see the available wireless connection just like XP does. Is this assumption correct, or might there be some more basic step that I should have performed?

[jetsam]

Ok. We haven't really gotten to work on the internet connection problem yet because the sudo problem came up. Wireless can be tough, or it can be easy, and I'll have to beg off on any more specifics than that because I'm personally utterly unfamiliar with it. Hopefully someone else can help get you going.

Can you sudo now? If you need a test case, try
sudo ls
It should ask you for your user password, and then give you a directory listing. It's important that sudo work; you'll need it for any further configuration that you do.

[Tim Silver]

Jetsam - brilliant - I can sudo! (I'd forgotten that we sorting sudo - like I said, it's an age thing)

Thank you

Now what do I do?

Oh yes, I remember. Continue with the 'sticky'!

[killdragon]

Hi,

I can only point you to something that worked for me

search for Scotsgait post from about a week ago.

He called it Hardy Headaches

[jetsam]

Killdragon: Thanks for that, but that thread is a less convoluted version of what just got fixed.

Tim: I'm glad there's been some progress and you're all set in the sudo department. I didn't realize you had to re-type everything, or I wouldn't have asked for so much output! You should be fine with Linux, though, with that kind of tenacity.

I was tired last night. The official Ubuntu documentation has the simple version of wireless that if you're lucky will do it for you:
https://help.ubuntu.com/8.04/internet/C/wireless.html
Have a look at it and try the stuff under "connecting using network manager" before you start digging into forum how-tos.

If wireless turns out to be giving you much grief, you might consider plugging in if it's possible. Wired connections can be a lot easier to get going. That's just me though; I have a tendency to recommend the things I understand over the things I don't. ;)

[kevdog]

wmaster0 is the wrong interface. Can you post your entire ifconfig?