Need to add a new subnet - should be an easy one for someone!

[Denda]

We run DHCP & are currently running out of ip addresses to lease out. We would like to add another subnet to our LAN/WAN. I need to know how to do this on our CISCO routers & switches. I've heard it can get pretty hairy & I want to make this as smooth of a change as possible.

We would like to add the following subnet 255.255.252.0 & then divide up the subnets like so
static - 10.53.1.0/22
DHCP - 10.53.2.0/22
Future - 10.53.3.0/22
10.53.10.0/24 - Remote Site DHCP

Below is one of our running configs.

version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname router01
!
enable secret 5 $1$79Wi$JHwsUAyctldXVEMf.vDTd/
!
!
!
!
!
clock timezone EST -5
clock summer-time EDT recurring
!
spanning-tree vlan 1 priority 100
ip subnet-zero
ip domain-name company.com
ip name-server 10.53.1.XXX
ip name-server 10.53.1.XXX
cluster enable ETHER 0
cluster member 1 mac-address 0001.9656.8d00
cluster member 2 mac-address 0001.9665.bf80
cluster member 3 mac-address 0001.96a2.fe40
cluster member 4 mac-address 0001.96b1.0cc0
cluster member 5 mac-address 0001.9653.dcc0
cluster member 6 mac-address 0001.9653.e140
cluster member 7 mac-address 0001.9643.1900
cluster member 8 mac-address 0001.9653.d500
cluster member 9 mac-address 0001.9653.f780
cluster member 10 mac-address 0001.96a3.3780
cluster member 11 mac-address 0001.9665.e380
cluster member 12 mac-address 0006.2819.ec00
!
cluster order 0,4,6,10,9,2,1,3,5,8,7,11,12
!
!
interface GigabitEthernet0/1
duplex full
!
interface GigabitEthernet0/2
duplex full
!
interface GigabitEthernet0/3
duplex full
!
interface GigabitEthernet0/4
duplex full
!
interface GigabitEthernet0/5
duplex full
!
interface GigabitEthernet0/6
duplex full
!
interface GigabitEthernet0/7
duplex full
!
interface GigabitEthernet0/8
duplex full
!
interface VLAN1
ip address 10.53.1.XXX 255.255.255.0
no ip directed-broadcast
ip nat outside
!
ip default-gateway 10.53.1.XXX
ip nat inside source list 199 interface VLAN1 overload
logging 10.53.1.XXX
access-list 199 dynamic Cluster-NAT permit ip any any
snmp-server engineID local 000000090200000196347640
snmp-server community cosnmp RO
snmp-server community cosnmp@es0 RO
snmp-server location Server room
snmp-server contact
snmp-server chassis-id 0x13
snmp-server host 10.53.1.XXX trap twbsnmp tty vlan-membership config c2900 vtp snmp

Any suggestions will be greatly appreciated. Thanks

 

[Namekian]

The second dhcp just needs to be in another network, so if you can create another network from what you have, then you can keep it. Like I said though, you will be using two networks, but they there shouldn't be anything to keep them from communicating from one another.

Also, you cant take 255.255.255.0 and change it to 255.255.252.0, if you were given 255.255.255.0 you can only further subnet that.

 

[Denda]

Ok - so the second network HAS to be 10.53.4.0 & it HAS to be in subnet 255.255.255.0. I create this on the router by one of the following:
int fa1/0
ip address 10.53.1.X 255.255.255.0
ip address 10.53.4.X 255.255.255.0 secondary

OR

int fa1/0.1
encap dot1q 1
ip address 10.53.1.X 255.255.255.0

int fa1/0.2
encap dot1q 2
ip address 10.53.4.X 255.255.255.0

CORRECT?

Well, just as a test, I changed my test environment:
switch (VLAN2 = 10.53.4.X 255.255.255.0)
pc (10.53.4.3 255.255.255.0)
And stopped there to test connectivity. No connectivity. Shouldn't this work like when I was using 10.53.2.X for my additional network? Or is there now more I need to do on the switch before I move to the router?

Once I get this working this way, won't all my internal traffic now go to my router for all traffic, not just external? That can't be good.

I don't know if this matters, but we do not run DHCP on the router, that is done by a Windows server.

Thanks a ton.

 

[Namekian]

You don't need to place VLANs on the switch if you are using the secondary IP option. And if you do end up using VLANS, then all traffic between the VLANS will be going through the router. If you use the secondary IP only external traffic will be going through your router.

Having a DHCP on the router or a windows box doesn't really matter. You will justs need the secondary IP or VLAN/subinterfaces to handle the different gateways out.

If you are doing the VLANS, as I am guessing you have it set up as now, make sure you place a routing protocal on the router to route between the network.
The simiplist protocol is rip:
Router(config)#router rip
Router(router-rip)#redistribute connected