dhcp_response probe fails to detect DHCP offer on RHEL 7.x

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

We have deployed dhcp_response probe (3.25) to a new build RHEL 7.9, dual-homed - Multiple NICS machine.

We are seeing:

- DHCP_response probe fails to issue DHCP request, using nominated IF, when it has no IP address

- DHCP_response probe fails to detect successful DHCP proffer from DHCP server (even though dhclient -r and then dhclient successfully gains a DHCP-lease on this IF and tcpdump shows successful request/offer.

Cause

The probe does not support multiple NIC/IP address.

Environment

Release : 20.3

Component : UIM - DHCP_RESPONSE

Resolution

The dhcp probe is unfortunately certified on RHEL 7.x 

Currently it can only run on RHEL 6.x

CA UIM Probes Support Matrix (broadcom.com)

 

The main issue with RHEL 7.x is that the probe does not support multiple NIC/IP address.

 

Additional Information

RHEL 7.x is going to be an outdated/unsupported version of Linux shotly.

Broadcom is working on bringing support for RHEL 8.x which should come soon. 

 

Alternative Approach:

If only a multiple NIC server can be used for monitoring the DHCP server an alternative customized approach can be followed. 

The following is a custom procedure and Broadcom support does not offer configuration support for it. 

The alternative method consists in using a custom script to release and renew the DHCP lease, redirect the output to a file and then use nexec and logmon to automate and monitor the result.