JUNIPER SRX1400 CLUSTER DHCP RELAY CONFIGURATION

Buon salve all,

how are you? How does proceed your digital life?

Today I speak you about a case I encountered some weeks ago. After an internet search, trying to solve the issue (you find it into the title) by myself, I don't find enough technical documentation; so I hope this post will help anyone of you will encounter the same problem.

So let's start. 

Technology involved: Juniper SRX 1400

Software release: JUNOS Software Release [12.1X46-D15.3]

Description: configuration, into a cluster environment, of the DHCP relay for reth X.Y. The examples and configurations, will follow, will be shown for reth 2.42 (my real and persona case).

First point - it's fundamental to have installed onboard at least the software release described above: the DHCP relay into a cluster environment is supported starting from this release and not before.

Second point - on your cluster juniper, from console type the following comand:

root# run show system processes extensive | grep dhcp

Check that the output of the command typed is:

1281 root        1  96    0 50280K 12060K select  19:38  0.00% jdhcpd

The important think is that you find jdhcpd and not dhcpd.

The dhcpd is the normal dhcp unders system services, and it's the usual way you can configure dhcp into a single environment. Obviously the jdhcpd is the only manner to configure dhcp and dhcp relay into a cluster environment. To enable the jdhcpd you can type the following command:

[edit]
set forwarding-options dhcp-relay server-group <sever-group-name> <ip-address>
set forwarding-options dhcp-relay active-server-group <server-group-name>
set forwarding-optoins dhcp-relay relay-option-60 vendor-option ……
set forwarding-options dhcp-relay group <group-name> interface <interface-name>

That, translated into my real case will produce the following configuration:

forwarding-options {
    dhcp-relay {
        server-group {
            DHCP-SERVER-XYZ {
                XXX.YYY.KKK.HHH;
            }
        }
        active-server-group DHCP-SERVER-XYZ;
        group DHCP-RELAY {
            interface reth2.42;
        }
    }
}

After done this, check again the output of the command:

root# run show system processes extensive | grep dhcp

Another command that can help you to understand if DHCP packets are exanched you cna type:

root# run show dhcp relay statistics

I hope this post can help you and you troubleshooting.

Have a nice day!

DiGiTsHaMaN