I'm trying to configure CUPS to allow remote administration through the web interface. There's enough documentation out there that I can figure out what to change in my cupsd.conf (changing Listen localhost:631 to Port 631, and adding Allow @LOCAL to the /, /admin and /admin/conf sections).
I'm now at the point where I can see the CUPS interface from another machine on the same network. The trouble is, when I try to Add Printer, I'm asked for a username and password, but my response is rejected even when I know I've gotten it right (I assume it's asking for the username and password of someone in the lpadmin group on the server machine; I've sshed in with credentials its rejecting, and the user I'm using has been added to the lpadmin group).
If I disable auth outright, by changing DefaultAuthType Basic to DefaultAuthType None, I get an "Unauthorized" error instead of a password request when I try to Add Printer.
What am I doing wrong? Is there a way of letting users from the local network to administer the print server through the CUPS web interface?
EDIT: By request, my complete cupsd.conf (spoiler: minimally edited default config file that comes with the edition of CUPS from the Debian wheezy repos):
LogLevel warn
MaxLogSize 0
SystemGroup lpadmin
Port 631
# Listen localhost:631
Listen /var/run/cups/cups.sock
Browsing On
BrowseOrder allow,
deny
BrowseAllow all
BrowseLocalProtocols CUPS dnssd
# DefaultAuthType Basic
DefaultAuthType None
WebInterface Yes
<Location />
Order allow,
deny
Allow @LOCAL
</Location>
<Location /admin>
Order allow,
deny
Allow @LOCAL
</Location>
<Location /admin/conf>
AuthType Default
Require user @SYSTEM
Order allow,
deny
Allow @LOCAL
</Location>
# Set the default printer/job policies...
<Policy default>
# Job/subscription privacy...
JobPrivateAccess default
JobPrivateValues default
SubscriptionPrivateAccess default
SubscriptionPrivateValues default
# Job-related operations must be done by the owner or an administrator...
<Limit Create-Job Print-Job Print-URI Validate-Job>
Order
deny,allow
</Limit>
<Limit Send-Document Send-URI Hold-Job Release-Job Restart-Job Purge-Jobs Set-Job-Attributes Create-Job-Subscription Renew-Subscription Cancel-Subscription Get-Notifications Reprocess-Job Cancel-Current-Job Suspend-Current-Job Resume-Job Cancel-My-Jobs Close-Job CUPS-Move-Job CUPS-Get-Document>
Require user @OWNER @SYSTEM
Order
deny,allow
</Limit>
# All administration operations require an administrator to authenticate...
<Limit CUPS-Add-Modify-Printer CUPS-Delete-Printer CUPS-Add-Modify-Class CUPS-Delete-Class CUPS-Set-Default CUPS-Get-Devices>
AuthType Default
Require user @SYSTEM
Order
deny,allow
</Limit>
# All printer operations require a printer operator to authenticate...
<Limit Pause-Printer Resume-Printer Enable-Printer Disable-Printer Pause-Printer-After-Current-Job Hold-New-Jobs Release-Held-New-Jobs Deactivate-Printer Activate-Printer Restart-Printer Shutdown-Printer Startup-Printer Promote-Job Schedule-Job-After Cancel-Jobs CUPS-Accept-Jobs CUPS-Reject-Jobs>
AuthType Default
Require user @SYSTEM
Order
deny,allow
</Limit>
# Only the owner or an administrator can cancel or authenticate a job...
<Limit Cancel-Job CUPS-Authenticate-Job>
Require user @OWNER @SYSTEM
Order
deny,allow
</Limit>
<Limit All>
Order
deny,allow
</Limit>
</Policy>
# Set the authenticated printer/job policies...
<Policy authenticated>
# Job/subscription privacy...
JobPrivateAccess default
JobPrivateValues default
SubscriptionPrivateAccess default
SubscriptionPrivateValues default
# Job-related operations must be done by the owner or an administrator...
<Limit Create-Job Print-Job Print-URI Validate-Job>
AuthType Default
Order
deny,allow
</Limit>
<Limit Send-Document Send-URI Hold-Job Release-Job Restart-Job Purge-Jobs Set-Job-Attributes Create-Job-Subscription Renew-Subscription Cancel-Subscription Get-Notifications Reprocess-Job Cancel-Current-Job Suspend-Current-Job Resume-Job Cancel-My-Jobs Close-Job CUPS-Move-Job CUPS-Get-Document>
AuthType Default
Require user @OWNER @SYSTEM
Order
deny,allow
</Limit>
# All administration operations require an administrator to authenticate...
<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>
# All printer operations require a printer operator to authenticate...
<Limit Pause-Printer Resume-Printer Enable-Printer Disable-Printer Pause-Printer-After-Current-Job Hold-New-Jobs Release-Held-New-Jobs Deactivate-Printer Activate-Printer Restart-Printer Shutdown-Printer Startup-Printer Promote-Job Schedule-Job-After Cancel-Jobs CUPS-Accept-Jobs CUPS-Reject-Jobs>
AuthType Default
Require user @SYSTEM
Order
deny,allow
</Limit>
# Only the owner or an administrator can cancel or authenticate a job...
<Limit Cancel-Job CUPS-Authenticate-Job>
AuthType Default
Require user @OWNER @SYSTEM
Order
deny,allow
</Limit>
<Limit All>
Order
deny,allow
</Limit>
</Policy>
