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Network Implementation with DHCP Relay Configuration

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Janarguna
Occasional Contributor

Network Implementation with DHCP Relay Configuration

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

3 REPLIES
Vince_Whirlwind
Trusted Contributor
Solution

Re: Network Implementation with DHCP Relay Configuration

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
Occasional Contributor

Re: Network Implementation with DHCP Relay Configuration

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
Established Member

Re: Network Implementation with DHCP Relay Configuration

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.