Hi,

As Neo has said, the most likely explanation here is that myuser has a valid shell set in /etc/passwd, whereas webuser does not.

Witness the following example:

Code:

# finger -l unixforum
Login: unixforum                        Name: 
Directory: /home/unixforum              Shell: /bin/bash
Never logged in.
No mail.
No Plan.
# finger -l test
Login: test                             Name: 
Directory: /home/test                   Shell: /bin/false
Never logged in.
No mail.
No Plan.
#

Here we start off as root. We see that the account unixforum has a shell of /bin/bash, whereas the account test has a shell of /bin/false - in other words, it will never be able to have any kind of interactive logon session.

Let's see what happens now if we try to switch through these, starting off again as root:

Code:

# whoami
root
# su - unixforum
$ whoami   
unixforum
$ su - test
Password: 
No directory, logging in with HOME=/
$ whoami
unixforum
$

We were able to switch user from root to unixforum without a password (something only root can do with su, as per rdrtx1's advice). However, when we tried to switch from unixforum to test it didn't work, since we can't get a shell prompt for a user that doesn't have a valid shell set.

Hope that this helps you to see a bit clearer how this works. If I've gotten the wrong end of the stick here and if what I'm describing doesn't match your problem, then if you can provide output for what's failing or otherwise give a more detailed description of what exactly isn't working we can take things from there.