This sounds like a disaster in the making.
Correct config is the customer lan is configured on eth0, or, bonded with say eth0 and eth3. That connects to your data switch. On your network is an accessible NTP server which the 4K will sync from. You administer the 4K by browsing to it over your data network.
Changes from yast are not supported, you stand a good chance of killing it. All other IP's are 0.0.0.0 because it must be a simplex system. If it's V6 R1 config is in the Portal, R1 did not support the config XML. If it's V6 R2 reconfiguration should be done via the XML (/var/opt/firstinstall/firstinst...xml) and recover_4k script.
Yes it's linux, you can do all kinds of things with it, but it's a realtime telephony system and the way it handles traffic internally between the VM's is complicated. If you make unusual changes, beware of unusual things happening.