en-US/configure-snmp-rhel.xml

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<section id="configure-snmp-rhel">
  <title>Configuring SNMP Community String on a RHEL Server</title>
  <para>The SNMP Community string is similar to a user id or password that provides access to a
    network device, such as router. This string is sent along with all SNMP requests. If the
    community string is correct, the device responds with the requested information. If the
    community string is incorrect, the device discards the request and does not respond.</para>
  <para>The NetScaler device uses SNMP to communicate with the VMs. You must install SNMP and
    configure SNMP Community string for a secure communication between the NetScaler device and the
    RHEL machine.</para>
  <orderedlist>
    <listitem>
      <para>Ensure that you installed SNMP on RedHat. If not, run the following command:</para>
      <screen>yum install net-snmp-utils</screen>
    </listitem>
    <listitem>
      <para>Edit the /etc/snmp/snmpd.conf file to allow the SNMP polling from the NetScaler
        device.</para>
      <orderedlist>
        <listitem>
          <para>Map the community name into a security name (local and mynetwork, depending on where
            the request is coming from):</para>
          <note>
            <para>Use a strong password instead of public when you edit the following table.</para>
          </note>
          <screen>#         sec.name   source        community
com2sec    local      localhost     public
com2sec   mynetwork   0.0.0.0       public</screen>
          <note>
            <para>Setting to 0.0.0.0 allows all IPs to poll the NetScaler server.</para>
          </note>
        </listitem>
        <listitem>
          <para>Map the security names into group names: </para>
          <screen>#      group.name   sec.model  sec.name
group   MyRWGroup     v1         local
group   MyRWGroup     v2c        local
group   MyROGroup     v1        mynetwork
group   MyROGroup     v2c       mynetwork</screen>
        </listitem>
        <listitem>
          <para>Create a view to allow the groups to have the permission to:</para>
          <screen>incl/excl subtree mask view all included .1 </screen>
        </listitem>
        <listitem>
          <para>Grant access with different write permissions to the two groups to the view you
            created.</para>
          <screen># context     sec.model     sec.level     prefix     read     write     notif
  access      MyROGroup ""  any noauth     exact      all      none     none
  access      MyRWGroup ""  any noauth     exact      all      all      all </screen>
        </listitem>
      </orderedlist>
    </listitem>
    <listitem>
      <para>Unblock SNMP in iptables.</para>
      <screen>iptables -A INPUT -p udp --dport 161 -j ACCEPT</screen>
    </listitem>
    <listitem>
      <para>Start the SNMP service:</para>
      <screen>service snmpd start</screen>
    </listitem>
    <listitem>
      <para>Ensure that the SNMP service is started automatically during the system startup:</para>
      <screen>chkconfig snmpd on</screen>
    </listitem>
  </orderedlist>
</section>