[sane-devel] Cascading saned servers

[Jens-U. Mozdzen]

Hi *,

I'm attempting to use cascading saned servers, in other words: I'm  
trying to share a scanner that is reachable from the "saned" system  
via its network back-end.

Technically, this works. Unfortunately, either saned or the clients  
are not prepared for this, as the network scanners are not not listed  
via "xsane" nor "scanimage -L".

The manual pages and network resources I found during my search seem  
ambiguous: Some people talk about "scanners local to the saned  
server", while the man page says "[saned] allows remote clients to  
access image acquisition devices available on the local host", which  
includes those reachable via network, too.

I've tested with saned from sane-backends-1.0.20-7.6.1 (SLES11SP3) and  
scanimage from sane-backends-1.0.23-9.2.3.i586 (Opensuse 13.1) and  
xsane-0.998-19.1.4.i586.

Machines involved:
- client machine (Opensuse 13.1)
- central saned server (SLES11SP3) "sanedserver.company.com"
- remote saned server (i.e. Opensuse 13.1)

When specifying the network scanner via "scanimage -d  
net:sanedserver.company.com:net:anothersanedserver.company.com:somedriver:somescanner" on the client machine, I can scan successfully, although running "scanimage -L" wouldn't list that device. "xsane" users are left out, as they're presented the same list as the one from "scanimage -L" , thus not seeing the cascaded scanner on the client  
machine.

Running "scanimage -L" on the central saned server will list the  
remote scanner.

We're using this design because of hub&spoke configurations, where  
remote saned servers will only permit the central server in their  
/etc/saned.conf and all clients connect only to the central saned  
server.

To be precise, it's the device listing that doesn't seem to work.  
Probably the central saned server doesn't report network-connected  
scanners to its clients. Is this "working as designed", or have I hit  
a bug?

Regards,
Jens