Using Cisco1900 router to divide LAN to two subnet

[drmohlen]

I was wondering if anyone can help me out here, I have got a single subnet LAN represeted by 192.168.1.x ip range which I am running out of IP addresses beaces I have used them all . I have purchased a cisco 1941 router to be able to divide the LAN to two subnet ( 192.168.1.x and 192.168.2.x)but using same windows 2k3 DHCP server with two scopes:

a)How do I configure my DHCP to have two scope but using one Default gateway?
b)How do I configure the router to do this for my?

BTW-I am new to Routers Please keep your reply simple.

Thanks

 

[DennyHeack]

a) impossible. 2 subnets = 2 default gateways.
You can, however, give 1 gateway 2 ip's....

b) I suggest you read the docs of Cisco.com first and 'try it' first and provide the questions as you encounter problems. This is too much to just explain in one simple reply...

 

[burtsbees]

I am not sure how to configure your DHCP server itself, but in the router you have to use "ip helper-address x.x.x.x" on the other vlan interface. I am not familiar with the 1941---2 fast ethernet interfaces? If so, just put an IP address on each...

router>en
router#config t
router(config)#int fa0/0
router(config-if)#ip add 192.168.1.1 255.255.255.0
router(config-if)#ip nat inside
router(config-if)#no shut
router(config-if)#int fa0/1
router(config-if)#ip add 192.168.2.1 255.255.255.0
router(config-if)#no shut
router(config-if)#ip helper-address 192.168.1.x (your DHCP server IP address)
router(config-if)#ip nat inside
router(config-if)#exit
router(config)#ip route 0.0.0.0 0.0.0.0 x.x.x.x (next hop)
router(config)#access-list 101 permit ip 192.168.1.0 0.0.1.255 any
router(config)#ip nat inside source list 101 int s0/0 over (assuming s0/0 is your WAN interface)

the config above is also for NAT...for a hostname...

router(config)#hostname YO
YO(config)#

You can configure your router to be a dhcp server too...

YO(config)#ip dhcp pool yo1
YO(dhcp-config)#network 192.168.1.0 255.255.255.0
YO(dhcp-config)#default-router 192.168.1.1
YO(dhcp-config)#dns-server x.x.x.x
YO(dhcp-config)#lease (whatever---do a ? for the options)
YO(dhcp-config)#import all (to import options from external dns from your ISP)
YO(dhcp-config)#exit
YO(config)#ip dhcp pool yo2
YO(dhcp-config)#network 192.168.2.0 255.255.255.0
YO(dhcp-config)#default-router 192.168.2.1
YO(dhcp-config)#dns-server x.x.x.x
YO(dhcp-config)#lease xxxxxxx
YO(dhcp-config)#import all
YO(dhcp-config)#end
YO#wr

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[burtsbees]

Denny---ever hear of PBR?

drmohlen---you don't need 1 gateway---each LAN can have their own (1.1 and 2.1), and they communicate with each other via the router by virtue of being directly connected---no additional routing statements necessary.

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[drmohlen]

Thank you Burtsbees for a quick reply, I could undrestand using the router as DHCP, currently my default gateway is the PIX firewal with 192.168.1.1
a) do I need to change any thing on the pix too?
b)don't get this command you mentioned:
ip nat inside source list 101 int s0/0 over (assuming s0/0 is your WAN interface)

can you please explain what this command does?
Thanks