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Manual Chapter: Configuration Guide for BIG-IP® version 9.2.2 Global Traffic Management: Working with SNMP - Appendix B
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B

Working with SNMP


Introducing SNMP in a BIG-IP system environment

The Global Traffic Manager ships with a customized simple network management protocol (SNMP) agent and management information base (MIB). This appendix describes the management and configuration tasks with which you can configure the Global Traffic Manager SNMP agent.

The Global Traffic Manager SNMP agent and Global Traffic Manager MIB allow you to monitor the Global Traffic Manager by configuring traps for the SNMP agent or by polling the system with a standard network management station. The Global Traffic Manager SNMP agent has the following options to ensure secure management:

  • Community names
  • TCP wrappers
  • View access control mechanism (VACM)

Using the Configuration utility, you can configure the Global Traffic Manager SNMP agent to send traps to your network management system. You can also set up custom traps by editing several configuration files.

Configuring SNMP on the Global Traffic Manager

To use SNMP on the Global Traffic Manager, you must complete the following tasks:

  • Download the Global Traffic Manager MIBs and load them into your network management station
  • Modify or verifty the following configuration files:
    • /etc/hosts.allow
    • /etc/hosts.deny
    • /etc/snmpd.conf
    • /etc/3dns_snmptrap.conf
    • /etc/syslog.conf
  • Configure options for the checktrap.pl script
Note

If you are configuring the Global Traffic Manager module on a BIG-IP system, you configure any SNMP settings using the BIG-IP Configuration utility. For information about working with SNMP on a BIG-IP system, refer to the Configuration Guide for Local Traffic Management.

Downloading the MIBs

The Global Traffic Manager includes a proprietary Global Traffic Manager SNMP MIB. This MIB is specifically designed for use with the Global Traffic Manager. You can configure the SNMP settings in the Configuration utility or on the command line.

SNMP management software requires that you use the MIB files associated with the device. You can obtain the following three MIB files from the /usr/local/share/snmp/mibs directory on the controller, or you can download the files from the Additional Software Downloads section of the Configuration utility home screen. The files you need are:

  • 3dns.my
    This is a vendor MIB that contains specific information for properties associated with specific Global Traffic Manager functionality, such as load balancing.
  • rfc1611.my
    This is a DNS server MIB (RFC 1611) that provides standard management information.
  • UCD-SNMP-MIB.txt
    This is a MIB-II (RFC 1213) that contains specific management information for the UC-Davis SNMP agent.

For information about the objects defined in 3dns.my, refer to the descriptions in the object identifier (OID) section of the MIB file. For information about the objects defined in rfc1611.my, refer to RFC 1611.

Understanding configuration file requirements

Before using the SNMP agent, you need to make changes to several configuration files on the Global Traffic Manager. You can make these changes either by using the Configuration utility or by modifying the files from the command line. Once you change these configuration files, you must restart the SNMP agent.

/etc/hosts.allow

The /etc/hosts.allow file specifies the hosts that are allowed to access the SNMP agent. You can configure access to the SNMP agent with the /etc/hosts.allow file in one of two ways:

  • By typing in an IP address, or list of IP addresses that are allowed to access the SNMP agent.
  • By typing in a network address and mask to allow a range of addresses in a subnet to access the SNMP agent
Warning

The /etc/hosts.allow file must contain the following entry, which is in the file by default: snmpd : 127.0.0.1. If you remove this entry, the Global Traffic Manager cannot properly poll using SNMP.

Adding a list of specific IP addresses to the /etc/hosts.allow file

You can specify a list of addresses that you want to allow access to the SNMP agent. Addresses in the list must be separated by blank space or by commas. Use the following syntax:

daemon: <IP address> <IP address> <IP address>

In the following example, the SNMP agent accepts connections from the specified IP addresses only:

snmpd: 128.95.46.5 128.95.46.6 128.95.46.7

Adding an address range to the /etc/hosts.allow file

For a range of addresses, the basic syntax is as follows, where daemon is the name of the daemon, and NETWORKADDRESS/MASK specifies the network that is allowed access:

daemon: NETWORKADDRESS/MASK

For example, the following syntax sets the snmpd daemon to allow connections from the 128.95.46.0/255.255.255.0 address range:

snmpd: 128.95.46.0/255.255.255.0

The previous example allows the 256 possible hosts from the network address 128.95.46.0 to access the SNMP daemon. You may also use the keyword ALL to allow access for all hosts or all daemons.

Note

If you prefer, instead of modifying this file from the command line, you can use the Configuration utility to specify the hosts that are allowed to access the SNMP agent. See To set SNMP properties using the Configuration utility .

/etc/hosts.deny

The /etc/hosts.deny file must be present to deny, by default, all UDP connections to the SNMP agent. The contents of this file are as follows:

ALL : ALL

/etc/snmpd.conf

The /etc/snmpd.conf file controls most aspects of the SNMP agent. This file is used to set up and configure certain traps, passwords, and general SNMP variable names.

The following list contains a few of the necessary variables:

  • System Contact Name
    The System Contact is a MIB-II simple string variable defined by almost all SNMP systems. It usually contains a user name and an email address. This is set by the syscontact key.
  • Machine Location (string)
    The Machine Location is a MIB-II variable that is supported by almost all systems. It is a simple string that defines the physical location of the system. This is set by the syslocation key.
  • Community String
    The community string clear text password is used for basic SNMP security. This also maps to VACM groups, but for initial read-only access, it is limited to only one group.
  • Trap Configuration
    Trap configuration is controlled by these entries in the /etc/snmpd.conf file:
    • trapsink <host>
      This sets the host to receive trap information. The <host> variable is an IP address.
    • trapport <port>
      This sets the port on which traps are sent. There must be one trapport line for each trapsink host.
    • trapcommunity <community string>
      This sets the community string (password) for sending traps. Once set, it also sends a trap upon startup: coldStart(0).
    • authtrapenable <integer>
      Set this variable to 1 so that traps can be sent for authentication warnings. Set the variable to 2 to disable it.
      Note: To change the trap port, be sure the trapport line precedes the trapsink line. If you use more than one trapsink line, there must be one trapport line before each trapsink line. The same is true for trapcommunity; if you use more than one trapcommunity line, there must be one trapcommunity line before each trapsink line.
  • System IP Setting
    You must set the system IP address using the sysip command; if this setting is not present, the checktrap.pl script fails to send all Global Traffic Manager-specific traps. Use the following syntax to set the system IP address:
  • sysip <Global Traffic Manager IP address>
Note

If you prefer, instead of modifying this file from the command line, you can use the Configuration utility to set these SNMP properties. See To set SNMP properties using the Configuration utility .

/etc/3dns_snmptrap.conf

The configuration in the /etc/3dns_snmptrap.conf file determines which messages generate traps and what those traps are. The file includes OIDS, traps, and regular expression mappings. The configuration file specifies whether to send a specific trap based on a regular expression. An excerpt of the configuration file is shown in Figure B.1

Figure B.1 Excerpt from the /etc/3dns_snmptrap.conf file
# Default traps.
.1.3.6.1.4.1.3375.1.2.2.2.0.1 (SNMP_TRAP: VS.*?state change green.*?red) VIRTUAL SERVER 
GREEN TO RED
.1.3.6.1.4.1.3375.1.2.2.2.0.2 (SNMP_TRAP: VS.*?state change red.*?green) VIRTUAL SERVER 
RED TO GREEN
.1.3.6.1.4.1.3375.1.2.2.2.0.3 (SNMP_TRAP: SERVER.*?state change green.*?red) SERVER 
GREEN TO RED
.1.3.6.1.4.1.3375.1.2.2.2.0.4 (SNMP_TRAP: SERVER.*?state change red.*?green) SERVER RED 
TO GREEN
.1.3.6.1.4.1.3375.1.2.2.2.0.5 (SNMP_TRAP: iQuery message from big3d) CRC FAILURE

.

Some of the OIDs have been permanently mapped to specific Global Traffic Manager events. The OIDs that are permanently mapped for the Global Traffic Manager include:

  • Virtual server green to red
  • Virtual server red to green
  • Server green to red
  • Server red to green
  • CRC failure
  • Pool green to red
  • Pool red to green
  • Global Traffic Manager active to standby
  • Global Traffic Manager standby to active

To see events that are triggering an SNMP trap, look in the var/log/3dns directory.

/etc/syslog.conf

To generate traps, you must configure syslog to send syslog lines to checktrap.pl. If the syslog lines match a specified regular expression in the 3dns_snmptrap.conf file, the checktrap.pl script generates a valid SNMP trap. The following line in the /etc/syslog.conf file causes the syslog utility to send the specified log output to the checktrap.pl script. The checktrap.pl script then compares the logged information to the 3dns_snmptrap.conf file to determine if a trap should be generated.

local2.warning | exec /sbin/checktrap.pl.

Note

If you uncomment this line, make sure you restart syslogd.

Configuring options for the checktrap.pl script

The checktrap.pl script reads a set of lines from standard input. The script checks each line against a set of regular expressions. If a line matches a regular expression, the script sends an SNMP trap.

The following options are available for the checktrap.pl script.

  • SNMP configuration file
    This file contains the SNMP variables. The checktrap.pl script gets trap configuration information from this file. The default is /etc/snmpd.conf.
  • snmpd_conf_file=<snmp configuration file>
  • SNMP trap configuration file
    This file contains the regular expression to SNMP trap OID mappings. It also contains a description string that is added to the trap message. The default is /etc/3dns_snmptrap.conf.
  • trapd_conf_file=<snmp trap configuration file>
  • SNMP trap program
    This program sends the SNMP trap. This program should be the snmptrap program included with the Global Traffic Manager. The default is /usr/local/bin/snmptrap.
  • trap_program=<snmp trap program>
  • Date removal
    This option turns off automatic date removal. Normally, each input line is expected to begin with a date. Typically, this date is removed before the trap is sent. This option keeps the date information in the trap. If you do not add this option, the date is removed from the trap by default.
  • no_date_strip
  • Usage
    This option prints a usage string.
  • usage

Configuring the Global Traffic Manager SNMP agent using the Configuration utility

You can use the Configuration utility to configure the following aspects of the Global Traffic Manager SNMP agent:

  • Client access
    You can define a specific network address or an address range from which SNMP requests are accepted. The Configuration utility adds the client access entries to the etc/hosts.allow file.
  • System information
    You can define a system contact, a machine location, and a community string. The Configuration utility adds the system information to the /etc/snmpd.conf file.
  • Trap configuration
    You can enter a trap sink and a trap community. The Configuration utility adds the trap configuration information to the /etc/snmpd.conf file.
Note

If you are configuring the Global Traffic Manager module on a BIG-IP system, you configure the SNMP settings in the BIG-IP Configuration utility.

To set SNMP properties using the Configuration utility

The Configuration utility provides sample SNMP settings for your reference. To use the Global Traffic Manager SNMP MIB, you must replace these sample settings with settings appropriate to your environment and your specific SNMP management software.

  1. In the navigation pane, click SNMP.
    The SNMP Configuration screen opens.
  2. Add the SNMP settings.
  3. For help on configuring the SNMP settings, click Help on the toolbar.
Warning

The /etc/hosts.allow file must contain the following entry, which is in the file by default: snmpd : 127.0.0.1. If you remove this entry, the Global Traffic Manager cannot properly poll using SNMP. When you use the Configuration utility to configure the systems's SNMP properties, this address is already listed in the Allow List box.

Configuring SNMP settings to probe hosts

After defining a host server or router, you need to configure its SNMP settings if you want to use SNMP to probe that host or router. Remember that you must first set up at least one SNMP prober factory on any BIG-IP system that runs the big3d agent and is in the same data center as the host or router.

The SNMP factory can collect some or all of the following information from a host or router:

  • Memory utilization
  • CPU utilization
  • Disk space utilization
  • Kilobytes/second throughput
  • Current connections
  • Packet rate

The Global Traffic Manager gathers metrics for BIG-IP systems, third-party load balancers andseveral host servers. Refer to Table B.1 for information on the host server types and the specific metrics that can be collected for each host type. To see the current performance of any of these server metrics, review the Metrics statistics screen.

Table B.1 Server types and the metrics collected by the Global Traffic Manager
Server Type or Operating System
Metrics collected:
Kilobytes/
Second
Packets/
Second
CPU
Memory
Disk
Current Connections
Nodes Up
BIG-IP system
X
X
     
X
X
Alteon® Ace Director
X
       
X
X
BSD, UC Davis
X
X
X
X
X
X
 
CacheFlow
X
X
X
   
X
 
Cisco® CSS series
X
X
     
X
X
Cisco LocalDirector
X
X
     
X
 
Cisco LocalDirector
X
X
     
X
 
Cisco SLB
         
X
X
Extreme
X
X
     
X
X
Foundry® ServerIron
X
X
     
X
X
Linux, UC Davis
X
X
 
X
X
X
 
NetApp® appliance
X
X
X
X
X
X
 
Sun® Solaris
X
X
X
   
X
 
Windows® 2000 Server
X
X
X
   
X
 
Windows NT® 4.0
X
X
X
X
 
X
 

 

Note

The Cisco LocalDirector metric shows new connections per second rather than current connections.

To configure host SNMP settings using the Configuration utility

  1. In the navigation pane, expand the Servers item, and click Host.
  2. From the Host column, click a host server.
    The Modify Host screen opens.
  3. On the toolbar, click SNMP Configuration.
    The Host SNMP Configuration screen opens.
  4. Add the SNMP settings for the host. For help on configuring the SNMP settings for a host, click Help on the toolbar.

Configuring the SNMP agent on host servers

For host probing to work properly, you need to verify that the SNMP agent is properly configured on the host itself. We recommend that you refer to the documentation provided with your host SNMP software for complete configuration information.

 




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