Now I need to configure DHCP server based on NW 6.5 for assigning IP
addresses to VLANs. The current configuration is as the following: the
DHCP server is up and configured with 1 subnet, for example 10.10.1.x/24.
During this configuration, another 2 more subnets will be created and
added on, for example, 172.16.1.x/24, 172.16.2.x/24. All above 3 subnets
will belong to 3 VLANs individualy but update infomation for the same
domain a.com.

What I understand is I need to create another two subnets for
172.16.1.x/24, 172.16.2.x/24. The question is whether I need to create
subnet pool for the VLANs above, based on the documentation of NW 6.5, I
was told for VLANs, one subnet pool needs to be created and associating
all above subnets to this subnet pool, is one subnet pool really required
for this configuration? Or, just curious, whether I could create 2 subnet
pools, one for 10.10.1.x/24, one for 172.16.1.x/24 and 172.16.2.x/24.

Another question is in the DNS based on NW6.5 at the same server, one
IN-ADDR.ARPA zone was already created for 10.10.1.x/24, for 172.16.1.x/24
and 172.16.2.x/24, could I just create one zone IN-ADDR.ARPA for
172.16.x.x, or I have to create one IN-ADDR.ARPA for 172.16.1.x/24 and
another one for 172.16.2.x/24?

Thank you for your kind advice.