fyi, I managed to make it work by restarting the network interface, and various tries:
- ifconfig eth0 IPofNAS netmask 255.255.255.0 down, then:
- ifconfig eth0 IPofNAS netmask 255.255.255.0 up
- pinged a machine of the network to check if networking is working
- Logged into DSM, set a static IP corresponding to the permanent DHCP lease for the nas
- disabled IPV6
I am now able to access the nas after reboots.