Table of content
Installation of an SNMP server providing access to management data such as networking activities, memory use, processes status, … Data will be shared read-only and protected by a simple password (aka: community string).
Build information
Ensure the following options:
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Configuration
The SNMP daemon is configured for a read-only access from the
community community-string
, only the
MIBs which are used will be exported.
It’s possible to split the configuration in two separate files, the
first one holding a generic configuration (snmpd.conf
), the
second one holding a configuration specific to the computer
(snmpd.local.conf
).
snmpd.conf
The information is shared read-only and is only protected by a
password: community-string
.
The 2c
version of the protocol is used.
The version 3
would have allowed a stronger security with the
integration of confidentiality, integrity and authentication.
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Set the different level of visibility for the MIBs, the information which will be published are about the network interfaces, resources (memory, process, disk), system status (temperature) and imap.
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AgentX (RFC 2741) is a protocol allowing external programs
to extend the SNMP agent with their own management information,
communication is done through the use of a UNIX socket. This will be
used, for example, by Cyrus IMAP with the OID
enterprises.3.6
.
If the agentx
group is not present on the system,
another appropriate group can be used (wheel
, …). Or
the group can be created using a free id number, here we use the
arbitrary value of 1025
:
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It is also possible to extend net-snmp with a perl script thank to the
embedded interpreter. Adding CPU temperature and frequency is done
through this script, in the UCD-SNMP-MIB::systemStats
branch.
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snmpd.local.conf
syslocation
and syscontact
entries need
to be tailored:
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During disk device analyses, the snmpd daemon can get stuck until a
timeout is reached. To avoid this situation the
ignoredisk
directive is used.
Extending
Temperature
Extending is done at the netSnmp
MIB, which is part of
UCD-SNMP-MIB::systemStats
.
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Startup
To allow automatic startup, the following line is added to the
/etc/rc.conf
file:
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MIBs
Information can be accessed by using a name instead of it’s numerical representation (OID). For that purpose a MIB definition must be installed.
If the MIB is not already present, it must be added and made available:
-
Adding (globaly or locally):
Adding to MIBs repository 1 2
cp my-mib.txt /usr/local/share/snmp/mibs/ # Adding globaly cp my-mib.txt $HOME/.snmp/mibs/ # Adding localy
-
Making available (one time usage, globaly, or localy):
Notify of new MIBs to use 1 2 3
export MIBS=+MY-MIB # One time usage echo "mibs +MY-MIB" >> /usr/local/etc/snmp/snmpd.conf # Global usage echo "mibs +MY-MIB" >> $HOME/.snmp/snmp.conf # Local usage