SNMP is the primary protocol for monitoring networking equipment; however, due to security and performance considerations, it was often a bad choice for servers. SNMP v 3 now has security improvements that make this a possibility for servers. For more on this, see RFC 3414. We have used Big Brother and Big Sister in the past, but it has always bothered us that a proprietary client was needed. Agatha once rolled out a huge Unicenter deployment, and the SNMP agent was so heavy that it took up most of the resources that the GNU/Linux box was using. SNMP has matured, and servers are relatively much more powerful now, so it seems reasonable to us that using stock SNMP management packages vs. proprietary should work well.
Our first step is to get the stock SNMP running on a CentOS / Red Hat v 4 system. We will use up2date to find out what SNMP packages are available, and download them:
[root@srv-1 usr-1]# up2date --showall | grep snmp net-snmp-5.1.2-11.EL4.6.i386 net-snmp-devel-5.1.2-11.EL4.6.i386 net-snmp-libs-5.1.2-11.EL4.6.i386 net-snmp-perl-5.1.2-11.EL4.6.i386 net-snmp-utils-5.1.2-11.EL4.6.i386 php-snmp-4.3.9-3.8.i386 [root@srv-1 usr-1]# up2date --get net-snmp-5.1.2-11.EL4.6.i386 --tmpdir=/root/ net-snmp-5.1.2-11.EL4.6.i386.rpm... ######################################## [root@srv-1 usr-1]# up2date --get net-snmp-libs-5.1.2-11.EL4.6.i386 --tmpdir=/root/ net-snmp-libs-5.1.2-11.EL4.6.i386.rpm... ######################################## [root@srv-1 usr-1]# up2date --get net-snmp-perl-5.1.2-11.EL4.6.i386 --tmpdir=/root/ net-snmp-perl-5.1.2-11.EL4.6.i386.rpm... ######################################## [root@srv-1 usr-1]# up2date --get net-snmp-utils-5.1.2-11.EL4.6.i386 --tmpdir=/root/ net-snmp-utils-5.1.2-11.EL4.6.i386.rpm... ######################################## [root@srv-1 usr-1]# up2date --get php-snmp-4.3.9-3.8.i386 --tmpdir=/root/ php-snmp-4.3.9-3.8.i386.rpm... ######################################## [root@srv-1 usr-1]# ls /root/*snmp* /root/net-snmp-5.1.2-11.EL4.6.i386.rpm /root/net-snmp-libs-5.1.2-11.EL4.6.i386.rpm /root/net-snmp-perl-5.1.2-11.EL4.6.i386.rpm /root/net-snmp-utils-5.1.2-11.EL4.6.i386.rpm /root/php-snmp-4.3.9-3.8.i386.rpm [root@srv-1 usr-1]# |
Now, let’s upgrade the existing SNMP packages:
[root@srv-1 ~]# for i in *.rpm; do rpm -Fvh $i; done [root@srv-1 ~]# rpm -qa | grep snmp net-snmp-libs-5.1.2-11.EL4.6 net-snmp-5.1.2-11.EL4.6 |
Let’s install the remainder:
[root@srv-1 ~]# for i in *.rpm; do rpm -i $i; done package net-snmp-5.1.2-11.EL4.6 is already installed package net-snmp-libs-5.1.2-11.EL4.6 is already installed [root@srv-1 ~]# rpm -qa | grep snmp net-snmp-libs-5.1.2-11.EL4.6 net-snmp-utils-5.1.2-11.EL4.6 net-snmp-perl-5.1.2-11.EL4.6 net-snmp-5.1.2-11.EL4.6 php-snmp-4.3.9-3.8 [root@srv-1 ~]# |
OK. Let’s start up the services and poke around:
[root@srv-1 init.d]# ./snmpd start Starting snmpd: [ OK ] [root@srv-1 init.d]# ./snmptrapd start Starting snmptrapd: [ OK ] [root@srv-1 init.d]# tail /var/log/messages Nov 9 16:23:22 srv-1 snmpd: snmpd startup succeeded Nov 9 16:23:22 srv-1 snmpd[20069]: Creating directory: /var/net-snmp Nov 9 16:23:22 srv-1 snmpd[20069]: NET-SNMP version 5.1.2 Nov 9 16:23:27 srv-1 snmptrapd[20077]: 2005-11-09 16:23:27 NET-SNMP version 5.1.2 Started. Nov 9 16:23:27 srv-1 snmptrapd: snmptrapd startup succeeded [root@srv-1 init.d]# |
We can use snmpwalk to show the available MIBs:
[usr-1@srv-1 ~]$ snmpwalk -v 1 localhost -c public SNMPv2-MIB::sysDescr.0 = STRING: Linux srv-1.example.com 2.6.9-22.0.1.EL #1 Thu Oct 27 12:26:11 CDT 2005 i686 SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10 SNMPv2-MIB::sysUpTime.0 = Timeticks: (30760) 0:05:07.60 SNMPv2-MIB::sysContact.0 = STRING: Root <root@localhost> (configure /etc/snmp/snmp.local.conf) SNMPv2-MIB::sysName.0 = STRING: srv-1.example.com SNMPv2-MIB::sysLocation.0 = STRING: Unknown (edit /etc/snmp/snmpd.conf) SNMPv2-MIB::sysORLastChange.0 = Timeticks: (11) 0:00:00.11 SNMPv2-MIB::sysORID.1 = OID: IF-MIB::ifMIB SNMPv2-MIB::sysORID.2 = OID: SNMPv2-MIB::snmpMIB SNMPv2-MIB::sysORID.3 = OID: TCP-MIB::tcpMIB SNMPv2-MIB::sysORID.4 = OID: IP-MIB::ip SNMPv2-MIB::sysORID.5 = OID: UDP-MIB::udpMIB SNMPv2-MIB::sysORID.6 = OID: SNMP-VIEW-BASED-ACM-MIB::vacmBasicGroup SNMPv2-MIB::sysORID.7 = OID: SNMP-FRAMEWORK-MIB::snmpFrameworkMIBCompliance SNMPv2-MIB::sysORID.8 = OID: SNMP-MPD-MIB::snmpMPDCompliance SNMPv2-MIB::sysORID.9 = OID: SNMP-USER-BASED-SM-MIB::usmMIBCompliance SNMPv2-MIB::sysORDescr.1 = STRING: The MIB module to describe generic objects for network interface sub-layers SNMPv2-MIB::sysORDescr.2 = STRING: The MIB module for SNMPv2 entities SNMPv2-MIB::sysORDescr.3 = STRING: The MIB module for managing TCP implementations SNMPv2-MIB::sysORDescr.4 = STRING: The MIB module for managing IP and ICMP implementations SNMPv2-MIB::sysORDescr.5 = STRING: The MIB module for managing UDP implementations SNMPv2-MIB::sysORDescr.6 = STRING: View-based Access Control Model for SNMP. SNMPv2-MIB::sysORDescr.7 = STRING: The SNMP Management Architecture MIB. SNMPv2-MIB::sysORDescr.8 = STRING: The MIB for Message Processing and Dispatching. SNMPv2-MIB::sysORDescr.9 = STRING: The management information definitions for the SNMP User-based Security Model. SNMPv2-MIB::sysORUpTime.1 = Timeticks: (7) 0:00:00.07 SNMPv2-MIB::sysORUpTime.2 = Timeticks: (8) 0:00:00.08 SNMPv2-MIB::sysORUpTime.3 = Timeticks: (8) 0:00:00.08 SNMPv2-MIB::sysORUpTime.4 = Timeticks: (8) 0:00:00.08 SNMPv2-MIB::sysORUpTime.5 = Timeticks: (8) 0:00:00.08 SNMPv2-MIB::sysORUpTime.6 = Timeticks: (8) 0:00:00.08 SNMPv2-MIB::sysORUpTime.7 = Timeticks: (11) 0:00:00.11 SNMPv2-MIB::sysORUpTime.8 = Timeticks: (11) 0:00:00.11 SNMPv2-MIB::sysORUpTime.9 = Timeticks: (11) 0:00:00.11 HOST-RESOURCES-MIB::hrSystemUptime.0 = Timeticks: (69894201) 8 days, 2:09:02.01 End of MIB |
If we specify one of the MIBs, we well see just that information:
[usr-1@srv-1 ~]$ snmpwalk -v 1 localhost -c public HOST-RESOURCES-MIB::hrSystemUptime.0 End of MIB HOST-RESOURCES-MIB::hrSystemUptime.0 = Timeticks: (69901531) 8 days, 2:10:15.31 [usr-1@srv-1 ~]$ |
From another machine on the same LAN:
[root@srv-7 ~]# snmpwalk -v 1 10.50.100.1 -c public HOST-RESOURCES-MIB::hrSystemUptime.0 End of MIB HOST-RESOURCES-MIB::hrSystemUptime.0 = Timeticks: (69984032) 8 days, 2:24:00.32 [root@srv-7 ~]# |
OK. Well, we are not running very securely. Our next article will deal with locking this down. Let’s stop the services in the mean time:
[root@srv-1 usr-1]# /etc/init.d/snmpd stop Stopping snmpd: [ OK ] [root@srv-1 usr-1]# /etc/init.d/snmptrapd stop Stopping snmptrapd: [ OK ] [root@srv-1 usr-1]# |
Note that to set up security, you will probably want the net-snmp-config command, and this is provided by the net-snmp-devel package. We ended up using yum to do this, and detailed the procedure in this article.
Related Post:SNMP MIB and OIDs – What are they and how do they work?
