Ubuntu – Differences between AWS Ubuntu Image and a fresh install

In the specific case of files for a web server, it's ok to simply give ownership of that directory to the ubuntu user.

 sudo chown -R ubuntu:ubuntu /var/www

Then you can drop files there easily.

You might also find some useful information about the EC2 user setup on Ubuntu in this article I wrote a while back:

Using sudo, ssh, rsync on the Official Ubuntu Images for EC2
http://alestic.com/2009/04/ubuntu-ec2-sudo-ssh-rsync

Happened to stumble across this thread on the Ubuntu forums, and thought it might help. It explains the steps that happen behind the scenes:

In Windows the client's username and password is automatically sent when it browses for shares - this is done without the user's knowledge. That forces Samba to deal with the sent credentials even though it's a guest share that requires no authentication.

When that username is passed Samba will search through it's password database for that user:

• If there is no match to the username the client user is tagged a "Bad User" and converted ( mapped ) to the guest account which by default is "nobody".

• If it finds a match to the username and there is a samba password that matches the one sent by the Windows client then the Windows user automatically gains access although not as an anonymous user which is why you needed to add "force user = nobody" to your share definition.

• If it finds a match to the username but the samba password does not match exactly the password that's automatically sent by the Windows client then you will be prompted for a password - even for a guest share.

Try adding force user = nobody to your share definition, and see if that does it.

Edit 02/20/2013:

Is testparm returning an exit code of something other than zero? All the same, I would go ahead and give that area of the config a good, hard look. Also, I'm not sure how case-sensitive smb.conf is, but every example I see (for example) of map to guest = Bad User has the B and U capitalized. Check-out the Samba man pages for the options you are using, and double-check everything.