vlans and DHCP

[The_guroo_2]

Guys i guess its pretty basic stuff and i am not 100% sure how ot do it :-)

I have one /24 address 10.12.14.0/24 and i have 3750 swicth and a ASA firewall. I need to configure DHCP as well choose IP for firewall inside interface as well for LAN.

I am thinking to do th follwoing and plz correct me guide me if i am wrong

ASA inside interface will be conect to 3750 so i will give 10.12.14.1/24 to ASA interface......will create vlan say vlan 10 on swicth and will config vlan 10 ip as 10.12.14.2/24 and will config DHCP scope on 3750 and will assign all other interfaces to vlan 10 (so that any one who connects to the interface gets vlan 10 IP from scope)

now is it right i will exclude the addresses. One thing i am not sure what shd be the default router ip and shd i give ip helper address under vlan 10??? i am sort of confuse am i at right track or not

thanks as always guys

[Henrik Grankvist]

If the 3750 is going to do the inter-vlan routing, don't forget to turn on routing on the switch:

S1(cofnig)#ip routing

Set the default-router in the dhcp pool to the switch's IP address of 10.12.14.2 and then on the switch set the gateway of last resort to the ASA's IP address:

S1(config)#ip route 0.0.0.0 0.0.0.0 10.12.14.1

You don't need an IP-helper in this case because the packet arrives on a switched-port and the switch is the DHCP server.

[The_guroo_2]

Why would I need routing on switch .....i will add default gateway to Asa and that's all there in only one vlan ...am I missing anything here

Sent from Cisco Technical Support iPhone App

[Henrik Grankvist]

No, you are right. If you are only going to use 1 vlan, that will not be a problem.

Just remember to make the router a member of vlan 10.

Default-gateway will be the ASA for the clients.