SNMP Collector displays source address as 127.0.0.1 in a VMware vCenter Server Appliance

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• SNMP traps in a SNMP collector sent from vCenter Server Appliance has source address of 127.0.0.1
• On the vCenter Server Appliance 5.1 and 5.0, tcpdump -w packetcapture.txt captures SNMP packets that appear similar to:
  
  Internet Protocol Version 4, Src: 192.168.1.10 (192.168.1.10), Dst: 192.168.1.9 (192.168.1.9)
  User Datagram Protocol, Src Port: 39610 (39610), Dst Port: snmptrap (162)
  Simple Network Management Protocol
  version: version-1 (0)
  community: public
  data: trap (4)
  trap
  enterprise: 1.3.6.1.4.1.6876.4.3 (iso.3.6.1.4.1.6876.4.3)
  agent-addr: 127.0.0.1 (127.0.0.1)
  generic-trap: enterpriseSpecific (6)
  specific-trap: 203

time-stamp: 94373252

Note: vCenter Server Appliance 5.5 does not have tcpdump to capture packets, a different method is used to capture packets.

Environment

VMware vCenter Server Appliance 5.0.x
VMware vCenter Server Appliance 5.1.x

Cause

This issue occurs because SNMP looks at the host file for the IP address of vCenter Server.

Resolution

To work around this issue, add the IP address and FQDN of vCenter Server Appliance to /etc/hosts file.

To add the IP address and FQDN of vCenter Server Appliance to /etc/hosts file:

1. Log in to the console of vCenter Server Appliance as the root user.
2. Change directory to /etc , using this command:
   
   cd /etc
   
   
3. Open the hosts file using a text editor.
4. Add the hostname in this format:
   
   vCenter_IP vCenter Server Appliance FQDN vcenter
   
   For example:
   
   10.10.10.10 vcenter.vmware.com vcenter
   
   
5. Save and close the file.
6. Run the vmware-vpxd service using this command:
   
   service vmware-vpxd restart

Additional Information

To be alerted when this document is updated, click the Subscribe to Article link in the Actions box Editing files on an ESX host using vi or nano