DHCP Relay Assistance - Server 2012 Load Balanced Configuration

[L1nklight]

I have a pair of Server 2012 DHCP servers setup in a load balanced configuration (50/50 split). Typically with a single DHCP server I would configure the following:

dhcp relay server-group 1 ip 192.168.0.2

inteface vlan-interface2

ip address 192.168.0.1

dhcp select relay

dhcp relay server-select 1

How would I go about adding multiple DHCP servers for the same pool? Say that my DHCP servers are 192.168.0.2. and 192.168.0.3. 

[Emil_G · Accepted solution]

Hi,

As far as I know you can add multiple servers to a single server-group. Here is the manual for the 5500 series (it is similar for other switches)

http://h20566.www2.hp.com/portal/site/hpsc/template.BINARYPORTLET/public/kb/docDisplay/resource.process/?spf_p.tpst=kbDocDisplay_ws_BI&spf_p.rid_kbDocDisplay=docDisplayResURL&javax.portlet.begCacheTok=com.vignette.cachetoken&spf_p.rst_kbDocDisplay=wsrp-resourceState%3DdocId%253Demr_na-c02645794-3%257CdocLocale%253D&javax.portlet.endCacheTok=com.vignette.cachetoken

Page 55

To improve reliability, you can specify several DHCP servers as a group on the DHCP relay agent and

correlate a relay agent interface with the server group. When the interface receives request messages

from clients, the relay agent will forward them to all the DHCP servers of the group.



By executing the dhcp relay server-group command repeatedly, you can specify up to eight DHCP server

addresses for each DHCP server group.

Not sure whether the addressing in your example would make sence (maybe this are just examples).

DHCP relay is typically used when DHCP server and DHCP clients are in different subnets.

I see that the DHCP servers and VLAN 2 interface IP on the switch are most probably in the same Ip subnet.

in this case the DHCP clients can reach the DHCP server directly on layer 2 and dont need the DHCP relay agent.

[L1nklight]

You're right about the example. There wouldn't really be a need to have the relay setup if it was relaying to the subnet it was already a part of. I checked some resources and came up with the following example:

dhcp relay server-group 1 ip 192.168.1.2
dhcp relay server-group 1 ip 192.168.1.3

inteface vlan-interface2
ip address 192.168.0.1
dhcp select relay
dhcp relay server-select 1

This seems to be working.