The Problem

My local glider club bought a new scanner / printer combination from Lexmark. The CX410de is a good office device which is able to print and also to scan documents. While printing was no problem at all, the scann-to-network function bugged me (and my colleague) a lot. Scans to a normal windows box worked like a charm (exactly as described in the manual) but scans to a share on our SME server (which is basically a Linux box that emulates a Windows domain controller and some shares) failed constantly ("Verbindung konnte nicht hergestellt werden. Kontaktieren Sie Ihren Administrator" - which translates to "Network connection could not be established. Contact your administrator").

The Solution

The interesting thing was that the scanner worked fine with plain windows shares which are hosted on windows boxes. After trying out all the possibilities in the settings of the printer/scanner combination i had to find a more systematic way to address this issue. I started to investigate how SMB network traffic looks like. Since tcp dump was installed i gave it a try: tcpdump -vv -p -s 0  port 445 or port 139 and src host 192.168.x.yyy

It turned out that SMB can communicate on port 139 and/or port 445 (see the TechNet post SMB over 139 or 445?). However, with a bit of luck I discovered that the SME Server was not listening on both ports. After adding them to the smb.conf and a quick restart of the service the scanner was able to find the network share and everything worked fine.

The upper listing shows the modified setting of the value "smb ports". It contains now both possible ports. The printer settings are as follows: