CentOS 7 SNMP 設定

安裝環境 : CentOS Linux release 7.5.1804 (Core)
getenforce : Disabled
firewall-cmd –list-services : http https ssh snmp

安裝套件

yum -y install net-snmp net-snmp-utils

設定 snmp 的定義

設定 192.168.1. 的網段可以透過 community nms01 讀取
設定 192.168.0. 的網段可以透過 community nms02 讀取

vi /etc/snmp/snmpd.conf

com2sec notConfigUser  default       public
com2sec local localhost public
com2sec mynetwork 192.168.1.0/24 nsm01
com2sec mytpnetwork 192.168.0.0/24 nms02

group MyRWGroup v1 local
group MyRWGroup v2c local
group MyROGroup v1 mynetwork
group MyROGroup v2c mynetwork
group MyROGroup v1 mytpnetwork
group MyROGroup v2c mytpnetwork

view    systemview    included   .1.3.6.1.2.1.1
view    systemview    included   .1.3.6.1.2.1.25.1.1

access  notConfigGroup ""      any       noauth    exact  systemview none none

view all    included  .1                               80

access MyROGroup "" any noauth prefix all none none
access MyRWGroup "" any noauth prefix all all all

syslocation New Taipei City, Taiwan
syscontact InfoTech <[email protected]>

dontLogTCPWrappersConnects yes

proc snmpd

disk / 10%

systemctl restart snmpd.service
systemctl enable snmpd.service

驗證與測試

主機端確認 snmp 服務有啟動

systemctl status snmpd.service
netstat -auntp | grep snmp

在網管端 Exp. 192.168.1.200 使用 snmpwalk -c nms01 進行檢測
```
snmpwalk -c public -v 2c 192.168.0.233
```

snmpwalk 結果出現
```
No Response from xxx.xxx.xxx.xxx
```

server log 出現類似

snmpd[942]: Connection from UDP: [192.168.xxx.xxx]:45239->[192.168.xxx.xxx]:161 REFUSED

可能就需要在 /etc/hosts.allow 裡面加入 snmp client 端的 IP Exp.192.168.1.240

/etc/hosts.allow

#
# hosts.allow   This file contains access rules which are used to
#               allow or deny connections to network services that
#               either use the tcp_wrappers library or that have been
#               started through a tcp_wrappers-enabled xinetd.
#
#               See 'man 5 hosts_options' and 'man 5 hosts_access'
#               for information on rule syntax.
#               See 'man tcpd' for information on tcp_wrappers
#
sshd:ALL
snmpd: 192.168.1.240

參考網址

NMS, snmp