[sane-devel] Scanner works, but networking does not

[Ralph Little]

Hi,

On 2021-07-08 7:28 p.m., E. Liddell via sane-devel wrote:
> Background:  I have a Canon LiDE 200 scanner, tested and confirmed to
> work with the genesys backend.  It's hooked up to a headless Raspberry Pi
> running Gentoo (*not* Raspbian, and it uses OpenRC, not systemd, for
> init) with a fairly minimal set of packages installed.  I want to share this
> scanner to another machine on my LAN.
>
> I have saned running.  The problem is that no matter how I configure it,
> it won't accept connections from anything but localhost.  This includes
> the host itself attempting to contact it by IP, which happens to be
> 192.168.1.51.
>
> Debug gives the error "argument marshalling error (Connection reset
> by peer)" regardless of what machine scanimage -L is running on, or
> what user it's running under.
>
> The problem is not likely to be general-networking or firewall-related
> (sshd works fine without having to drill holes anywhere, and I can see the
> open saned port when running nmap from a different machine).
>
> /proc/sys/net/ipv6/bindv6only contains a 0, so that isn't an issue (and sshd
> would be broken if it were).
>
> avahi support is not compiled into sane (it causes errors), but I don't see
> why that would cause this type of breakage.
>
> The saned user is in the usb and scanner groups.
>
> What have I missed?
>
> ====
>
> saned.conf, minus comments:
>
> 192.168.1.55
> 192.168.1.51
> 192.168.1.52
> 192.168.1.0/24
> localhost
>
> ====
>
> net.conf, minus comments:
>
> connect_timeout = 60
>
> 192.168.1.51
> localhost

The config looks OK.

Firstly, let's check the obvious: do you have a firewall activated on 
the Pi?

Failing that , would it be possible to get some diag from saned itself? 
It looks like the problem is there.
saned outputs diag with the "-d 128" option. By default it outputs to 
syslog, but if you use -e the output goes to stderr instead. Details: 
man saned
I don't know anything about the setup of how saned is started with 
OpenRC. If you cannot get diag output from it somewhere, then I can see 
if I can figure something out here.

Cheers,
Ralph