Putting together a new DHCP scope with DNS access in our network without outage if possible.

Dear experts,

I have two sides of the building and one (north side) we want to put in another VLAN IP network.

We are running out of IP's that is part why.

So here is my plan.

We have two switches connected with one another via cat 5 cable.

Switch north-side port 48 trunks to south-side switch to  trunk port  1.

looks like this:

interface GigabitEthernet0/1
 description  Southside Switch
 switchport access vlan blah
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 10,15,30,255 <--- need to add vlan 201
 switchport mode trunk

*****************************************  

North side switch:

interface GigabitEthernet0/48
 switchport access vlan 10
 switchport trunk encapsulation dot1q       <----------- Trunk port
 switchport mode access
!


VLAN I already created in the north-side switch:

interface Vlan201
 description It network north side of building
 ip address 172.16.201.254 255.255.255.0
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 7 "key"
 ip ospf cost 10
 ip ospf 10 area 172.16.201.0


Everything physical is in the south side. The north side is just an extension with a switch. Both switches are Cisco 3560s.

The new network will be (for this post I changed from real IPs) VLAN 201 IP: 172.16.201.0 255.255.255.0

Everyone in the north-side is in VLAN 10 we need to move them to VLAN 201.

We have a core router or a "router on the stick" that should have the following entry:

 interface GigabitEthernet0/0.201  <----------- needed  sub interface entry
 encapsulation dot1Q 10
 ip address 172.16.201.1 255.255.255.0
 ip accounting access-violations
 ip pim dense-mode
 ip nat inside
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 7 "keynumber"
 ip ospf lls disable
 no cdp enable

Plus the network statement in the OSPF configuration.

 network 172.16.200.0 0.0.0.255 area 172.16.200.0

OSPF is needed here for inter routing with other locations.

I am thinking of configuring the DHCP service on the actual Core Router. That should have the DNS entry for the clients pointing at the current DNS servers.

So the IP's should look like 172.16.201.x....  DNS 172.16.200.42 172.18.200.42

I need to make sure Printers and workstations connected in the north-side changed of IP smoothly as possible. Is there a way to do it without having to reboot or release the old DHCP IP address?

I need to identify how many mac addresses are per port in the north-side switch. Here are none trucking ports with more than one mac address running:

north-sideswtch#sh mac address-table interface gigabitEthernet 0/21
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
  10    24be.0513.8f26    DYNAMIC     Gi0/21
  10    f4ce.46f4.0515    DYNAMIC     Gi0/21

north-sideswtch#sh mac address-table interface gigabitEthernet 0/30
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
  10    001d.b3db.8a70    DYNAMIC     Gi0/30
  10    0024.811f.c531    DYNAMIC     Gi0/30
Total Mac Addresses for this criterion: 2
 
 
 
north-sideswtch#sh mac address-table interface gigabitEthernet 0/35
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
  10    0025.b376.5962    DYNAMIC     Gi0/35
  10    0090.a9f4.f5d7    DYNAMIC     Gi0/35
  10    b4b5.2fbf.b8a2    DYNAMIC     Gi0/35
  10    c434.6b5e.0215    DYNAMIC     Gi0/35



Also the gateway to the internet. If I need to have more than one VLAN in that north-side switch what should the gateway be?

Thanks for any help.

M