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I am in 4 floor Building. See diagram attached.
Each floor is divided into 2 sides “F” & “B”, F=left & B=right.
And each side has a 24-port 3com super stack III 3226 switch (S1-S7).
And each switch per side has up to 28 user/pc.
Each floor has 2 printers one on each side, HP Lasejet 4200 (P1-P7).
And one HP Color LaserJet CP3525 in the server room (P8).
Each switch is connect via fiber to a main switch in
a server room “netgear gsm 7312” (S8).
I have 17 server in the server room with static ip-addresses.
My network is now 192.168.0.0/23. Gateway=192.168.0.1 DNS1=192.168.0.3 DNS2=192.168.0.146 DHCP=192.168.0.3 NETMASK=255.255.254.0.
I have one Scope in DHCP: Start=192.168.0.1 & End=192.168.1.254, lease for 1 day.
I want to segment my network so that each floor side is on its own network, and can access the servers.
Like This:
Netmask: 255.255.255.224 = 27
All the printers has static ip-addresses.

4B- Network=192.168.0.224/27  Broadcast=192.168.0.255   IPs=192.168.0.225-254
4F- Network=192.168.0.192/27 Broadcast=192.168.0.223   IPs=192.168.0.193-222
3B- Network=192.168.0.160/27 Broadcast=192.168.0.191   IPs=192.168.0.161-190
3F- Network=192.168.0.128/27 Broadcast=192.168.0.159   IPs=192.168.0.129-158
2B- Network=192.168.0.96/27   Broadcast=192.168.0.127   IPs=192.168.0.97-126
2F- Network=192.168.0.64/27   Broadcast=192.168.0.95    IPs=192.168.0.65-94
1B- Network=192.168.0.32/27   Broadcast=192.168.0.63    IPs=192.168.0.33-62
1F- Network=192.168.0.0/27     Broadcast=192.168.0.31    IPs=192.168.0.1-30

Plus I have 2 Cisco RV082 Router (R1-R2) that I will use to setup an IPsec VPN connection over the internet to do a server to server backup.
All the Servers will have a “1F” ip-addresses.
All the pc will be DHCP.
All the pc will be on the Domain “testnet.com”

How do I set this up if all my servers are Windows Server 2008 R2?
How do I configure Active Directory, DHCP & DNS to work with this setup?

BTW: my AD, DHCP & DNS are on one server 192.168.0.3, but I would like to have a failover/load balancer on another server 192.168.0.146, how can this be done?

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  • Latest Post Latest Post by JorgeM

Dani AI

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A concise, practical checklist that fills gaps from the replies

  • : a /27 gives 30 usable addresses — with up to ~28 users per switch that leaves almost no breathing room for phones, APs, prints, management IPs or reservations. Consider using /26 (62 usable) or reserve an adjacent block so each side has growth headroom.

  • Use VLANs for each “side” and do routing at a single Layer‑3 point (your core switch or a router). The Netgear GSM7312 you mentioned is a Layer‑3 managed switch capable of routed VLANs/SVIs, so you can host each subnet’s gateway there and keep inter‑VLAN routing local. (manuals.plus)

  • DHCP HA: on WS2008 R2 you don’t get Microsoft DHCP lease‑replication built in — common options were split scopes or clustering. True DHCP failover (lease replication between two DHCP servers) was added in Windows Server 2012; if you need seamless failover, plan an OS upgrade or accept split‑scope/clustering tradeoffs. (learn.microsoft.com)

  • AD/DNS best practices to add on top of ’s advice: map your new subnets into Active Directory Sites and Services so clients use local DCs and replication schedules match physical links; make DNS zones AD‑integrated and enable scavenging for stale records; authorize any DHCP servers in AD and decide whether DHCP or clients will perform DNS updates (DHCP can update on clients’ behalf but needs proper credentials or DnsUpdateProxy handling). (learn.microsoft.com)

Quick rollout plan (safe steps)

  1. Plan addressing (leave spare addresses). 2) Create VLANs + SVIs on core, assign gateways. 3) Create DHCP scopes (one per VLAN) and test on a single floor. 4) Promote second DC, configure AD sites, enable DNS replication and scavenging, then enable DHCP HA or split scope and test failover. Example SVI (replace placeholders):
interface vlan 10
 ip address <VLAN10_GATEWAY> <MASK>
 ip helper-address <DHCP1_IP>
 ip helper-address <DHCP2_IP>

Focus first on one floor/VLAN, validate client boot/DNS/AD logons, then roll out.

Member Avatar for JorgeM

On the current Active Directory server (192.168.0.3), you should already have a DNS zone for the domain (testnet.com). Get the OS set up on the second server. Point its DNS configuration to the existing DC. Run DCPROMO, during the wizard, join an existing forest, existing domain. Provide admin credentials, finish the AD installation, restart.

Install DNS on the second server. If the DNS zone on the first DC is Active Directory integrated in scope, the DNS zone will replicate according to AD and show up on the second DNS server.


Video: Install the windows Server 2008 DNS Service

DNS Client Configuration for Domain Controllers

Setup DHCP on this second server as well. Configure the scopes on the first DC to host only 50% of the available leases. Set up the same scopes on the second DHCP server and host the other 50% of the leases.

Load Balancing DHCP Using Split Scopes

For each vlan in your network, configure the relay agent to point to both DHCP servers. That way either server will service your clients. If one DHCp server fails, you still have the other one servicing.

In your DHCP scopes, make sure that you configure your clients to point to both DNS server (DC1 and DC2).

That's pretty much it at a very high level. Absorb this info and come back with additional questions.

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