Infrastructure network services (DNS, NTP...)

DNS

The default gateway usually (depending on the network) works as a DNS server. In any case, the DNS servers to be used are pushed by the DHCP when the VM starts, so the DHCP client of the image must be configured (if this is not already the case) to use this dynamic configuration.

NTP

In all configurations, an NTP server is present on your subnet and responds to broadcast time synchronization requests. Simply fix the configuration of the ntpd daemon as follows (/etc/ntp.conf):

[...]
broadcastclient
[...]