Ubuntu + CUPS = Cannot Admin via {hostname}:631

[LydaRA]

I wish I did understand. I've read the docs for 1.5 (the version bundled with Ubuntu 12.04). And yet I don't see any mention of creating a user or specifying what user CUPS processes will run as. I did see settings for authentication types to use the host UNIX users, but the system still doesn't seem to be able to handle comparing the incoming web credentials to the system and continue to the admin web pages...

I think this may be more of an issue with something about Ubuntu's setup of CUPS than CUPS internal? Is there not a complete step-by-step guide for Ubuntu 12 installation of CUPS?

[dannyboy79]

is there a lpadmin group? Add your username to that group.

here's the cups server guide for 12.04: https://help.ubuntu.com/12.04/serverguide/cups.html

[redmk2]

is there a lpadmin group? Add your username to that group.

here's the cups server guide for 12.04: https://help.ubuntu.com/12.04/serverguide/cups.html

Exactly!

Configure printers

This right is gained by adding the user to the "lpadmin" group.

Cups contains a setting called "SystemGroup" in the /etc/cusp/cupsd.conf that specifies who is allowed to manage printers. By default, it is set to "lpadmin".

Search on lpadmin at this site

[LydaRA]

Yes, the account is in the lpadmin group, as shown by

getent group | grep lpadmin
lpadmin:108:sysop,papercut,root

[LydaRA]

As posted earlier, I've also added root, sysop, and the Windows AD group to the SystemGroup line in cupsd.conf:

SystemGroup root sysop lpadmin HHP\PrinterAdmins

Is that syntax correct? Or is that a possible problem (listing UNIX users & groups, and AD users and groups together)?

[redmk2]

As posted earlier, I've also added root, sysop, and the Windows AD group to the SystemGroup line in cupsd.conf:


Is that syntax correct? Or is that a possible problem (listing UNIX users & groups, and AD users and groups together)?

No, the lpadmin group should hold only local users (from this localhost). Linux has no nested groups. I would expect that only users that have sudo rights can configure CUPS. This means the user also should be a member of the sudo group (an administrator).

lpadmin group

redmk2@maui:~$ getent group|grep lpadmin
lpadmin:x:109:redmk2

Member of sudo group

redmk2@maui:~$ getent group|grep sudo
sudo:x:27:redmk2

The groups redmk2 is a member of

redmk2@maui:~$ getent group|grep redmk2
adm:x:4:redmk2
cdrom:x:24:redmk2
sudo:x:27:redmk2
dip:x:30:redmk2
plugdev:x:46:redmk2
lpadmin:x:109:redmk2
redmk2:x:1000:
sambashare:x:124:redmk2

Generally speaking, you should administer CUPS from the local host. If you must do this remotly you can ssh to that host and use the lpadmin commands directly. See

man lpadmin

... or config the CUPS admin web page to accept the ethernet connection.

[LydaRA]

getent group | grep lpadmin
lpadmin:x:108:sysop,papercut,root

getent group | grep sudo
sudo:x:27:sysop,papercut

So I still don't see how the CUPS process (whatever user that is) can access the UNIX users password file to verify the credentials passed in...

I find references to "cupsys" on some sites, but it appears that Ubuntu uses a "cups" name instead--although I fail to find either "cupsys" or "cups" as a user to add to the shadow group...

[dannyboy79]

have you checked to see what user does run the cups server? I am now curious

ps aux | grep cups

i believe the problem with ubuntu's implementation of CUPS is because Ubuntu disables the root account by default. I admit after just googling and reading about CUPS I am confused about it just as much as you. Did you run
sudo apt-get install cupsys
or
sudo apt-get install cups

[redmk2]

getent group | grep lpadmin
lpadmin:x:108:sysop,papercut,root

getent group | grep sudo
sudo:x:27:sysop,papercut

So I still don't see how the CUPS process (whatever user that is) can access the UNIX users password file to verify the credentials passed in...

I find references to "cupsys" on some sites, but it appears that Ubuntu uses a "cups" name instead--although I fail to find either "cupsys" or "cups" as a user to add to the shadow group...

The CUPS process is run by the system user lp. This user is NOT the same as the user that administrates the system (e.g. lpadmin). The cupsys reference is to an ubuntu package. There is no user cups.

What is your login? I assume you are a user with sudo rights. Are you a member of the group lpadmin. Are you able to administrate CUPS?

[AlexDudko]

<Limit CUPS-Add-Modify-Printer CUPS-Delete-Printer CUPS-Add-Modify-Class CUPS-Delete-Class CUPS-Set-Default>
AuthType Default
Require user @SYSTEM
Order deny,allow
</Limit>

This is default for Ubuntu (and maybe other sudo based distro's) and usually there's no need to change anything. It works good and allows logins with the admin user name and its password.
The admin user is the user which was created within the system installation procedure.
But if root user is set then to log in you must enter root as login name and root password. (This is usually default for su based distro's).