Network Implementation with DHCP Relay Configuration

[Janarguna]

HI,

I have a single layer3 switch connected to 5 layer 2 switches and a dhcp server. Please find the attached file for your reference.

I have 13 different vlans and also i have configured 13 different scopes with respect to the vlan.

I havent done done any configuration on the switches other than creating 13 vlans and assigned an IP address to it. With respect to dhcp configuration all the default gateway will the 13 ip's on the switch. 

Help me to configure inter vlan routing and dhcp relay so that all the host can get IP address from dhcp server and communicate between them.

Thanks in advance

[Vince_Whirlwind · Accepted solution]

With the IP addresses configured on each VLAN interface, enable ip routing and the switch will route between them without any more config required.

To get DHCP requests to be forwarded to your server from all the VLANs, add this to each VLAN interface:

ip helper-address 10.1.2.3

where "10.1.2.3" is the IP address of your DHCP server.

[Janarguna]

HI ,

Thank you so much for your valuable input. I am using HP A5500 switch, and i have configured ip address to all vlans on the core switch. 

Help me with the command to enable ip routing and I am unable to give ip helper address on vlan interface. I guess here it has to be configured with dhcp relay.

Kindly confirm and thank you so much for your help.

Thanks,

Jana

[Acmosa]

As said in previous post. The switch will route automatically between vlans with ip assigned vlan interfaces.

To be able to us one dhcp server for the different vlans you need to create a dhcp relay server group.

Create DHCP relay server group:

dhcp relay server-group 0 ip 1.2.3.4

Enable UDP helper:

udp-helper enable

Create vlan interface, enable dhcp relay and assign group 0 with server-select 0

interface Vlan-interface2
  ip address 2.3.4.1 255.255.255.0
  dhcp select relay
  dhcp relay server-select 0

You only need one server-group per DHCP server.

 I hope this solves your question.

[Yann75]

Hello,
Sorry to release an old topic.
I think on my HP 5900AF, it's the same.

Small clarification the DHCP replay server group points to my DHCP server?
For the VLAN interface I enable the DHCP relay and the ip address must match the scope created on the DHCP of my server Windows 2012 server?
How else to link with the vlan and my DHCP scope?

Thanks for your help.

Yann