Hi all,

We are trying to upgrade our CUPS linux printing service by creating two 
print servers.  These servers will be identically configured (i.e. 
identical printer queue names etc) to try and give us redundancy.  We 
have had success with an SL 4.4 client running CUPS 1.1.22 but found 
problems with an SL 5.1 client running CUPS 1.3.7.

Details:

By creating identical print servers we make use of CUPS' implicit 
classes.  If we stop the cups service on our "second" print server - 
FQDN2 below - (i.e. to simulate failure or re-configuration), we see the 
following:

SL 4.4: All printers are still available.  (Using remaining print server)
SL 5.1: All printers disappear.  (Even though remaining server is active)

The cups log of the SL 5.1 client explicitly states that it is polling 
both of the configured print servers.

Has anyone discovered the same problem?  Is there an easy work around?  
Does an upgrade to SL 5.2 fix this?

More details and cups configuration files below.
Any help appreciated!
Jon

++++

++ SL 4.4 system:

# yum list installed | grep cups
cups.i386                                1:1.1.22-0.rc1.9.27.el installed
cups-devel.i386                          1:1.1.22-0.rc1.9.27.el installed
cups-libs.i386                           1:1.1.22-0.rc1.9.27.el installed
hal-cups-utils.i386                      0.5.2-8                installed
libgnomecups.i386                        0.1.12-5               installed


(Config file with server names masked.)
# cat /etc/cups/cupsd.conf

# basic cupsd.conf for clients

LogLevel info
# LogLevel debug

HostNameLookups On

Browsing On
BrowseShortNames Yes
BrowseOrder allow,deny
BrowseDeny All
BrowsePoll FQDN1:631
BrowsePoll FQDN2:631

ImplicitClasses Yes
ImplicitAnyClasses Yes
HideImplicitMembers Yes

DefaultAuthType Basic

<Location />
  Order Allow, Deny
  Allow localhost
</Location>

<Location /admin>
  AuthType Basic
  Require user @SYSTEM
  Order Allow, Deny
  Allow localhost
</Location>
BrowseProtocols cups
Listen localhost:631
Listen /var/run/cups/cups.sock


++ SL 5.1 system

# yum list installed | grep cups
cups.i386                                1:1.3.7-8.el5_3.6      installed
cups-libs.i386                           1:1.3.7-8.el5_3.6      installed
hal-cups-utils.i386                      0.6.2-5                installed
libgnomecups.i386                        0.2.2-8                installed


(Config file with server names masked.)
# cat /etc/cups/cupsd.conf

# basic cupsd.conf for clients

LogLevel info
# LogLevel debug

HostNameLookups On

Browsing On
BrowseShortNames Yes
BrowseOrder allow,deny
BrowseDeny All
BrowsePoll FQDN1:631
BrowsePoll FQDN2:631

ImplicitClasses Yes
ImplicitAnyClasses Yes
HideImplicitMembers Yes

DefaultAuthType Basic

<Location />
  Order Allow, Deny
  Allow localhost
</Location>

<Location /admin>
  AuthType Basic
  Require user @SYSTEM
  Order Allow, Deny
  Allow localhost
</Location>

Listen localhost:631
Listen /var/run/cups/cups.sock

-- 
----------------------------
Jon Clark
Scientific Officer
Dept. of Applied Mathematics
University of Sheffield
Sheffield, S3 7RH, UK
----------------------------