CentOS构造SNMP

<span style="font-size:14px;">本文介绍怎样在CentOS环境下配置一个简单的SNMP服务</span>

软件安装

切换到系统管理员帐户

安装snmp
确认snmp代理已安装
rpm -q net-snmp
假设未安装。安装snmp
yum install net-snmp

设置开机自己主动执行snmp
/sbin/chkconfig snmpd on配置snmp

改动配置文件

将原来的配置文件备份。编辑/etc/snmp/snmpd.conf，简单配置例如以下

# First, map the community name "public" into a "security name"

#       sec.name  source          community
com2sec notConfigUser  default       public

####
# Second, map the security name into a group name:

#       groupName      securityModel securityName
group   notConfigGroup v1           notConfigUser
group   notConfigGroup v2c           notConfigUser

####
# Third, create a view for us to let the group have rights to:

# Make at least  snmpwalk -v 1 localhost -c public system fast again.
#       name           incl/excl     subtree         mask(optional)
view    systemview    included   .1.3.6.1.2.1.1
view    systemview    included   .1.3.6.1.2.1.25.1.1

####
# Finally, grant the group read-only access to the systemview view.

#       group          context sec.model sec.level prefix read   write  notif
access  notConfigGroup ""      any       noauth    exact  systemview none none

启动snmp

/etc/init.d/snmpd start
假设已启动则重新启动snmp服务
/etc/init.d/snmpd restart

測试snmp

查看port是否打开
netstat -ln | grep 161

安装snmp測试工具
yum install net-snmp-utils

本机測试snmp数据（改动monit为配置的团体名）
snmpwalk -v 2c -c public localhost system

snmpwalk -v3 -u username -l auth -a MD5 -A password localhost

创建SNMP（v3）用户

net-snmp-config --create-snmpv3-user -ro -a MD5 lyceemsnmp lyceem.com

远程測试snmp数据（改动ip为serverip，snmpwalk命令须要安装net-snmp）
snmpwalk -v 2c -c public ip system

故常处理

错误排除假设本地測试snmp有数据。远程測试snmp无数据则因为server防火墙禁止了外部訪问serverudp 161port，则：
改动 /etc/sysconfig/iptables （或者：/etc/sysconfig/iptables-config ），添加例如以下规则：
-A RH-Firewall-1-INPUT -p udp -m state Cstate NEW -m udp Cdport 161 -j ACCEPT
重新启动iptables
/etc/init.d/iptables restart