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.