Switch#configure terminal 
Enter configuration commands, one per line. 
Switch(config)#
Switch(config)#snmp-server community public RO 
在這里public是RO（只讀）的共同體的密碼
Switch(config)#snmp-server community PRivate RW 
在這里private是RW(讀寫)的共同體的密碼
Switch(config)#exit 
退出
Switch#write memory 
Building configuration...存盤

出于網絡安全的考慮，一是密碼需要修改為較安全的密碼，二是不建議設置RW（讀寫）的SNMP設置。
2.假如是Cisco 3550交換機的話，配置SNMP如下：

snmp-server community public RO 
snmp-server community private RW

3.Cisco 7507路由器

snmp-server community public RO

4.Cisco PIX520防火墻

snmp-server community public

其實在Cisco設備上進行SNMP設置的命令基本上是一樣的。

172switch#show snmp
Chassis: 0x10
52530 SNMP packets input
0 Bad SNMP version errors
0 Unknown community name
0 Illegal Operation for community name supplied
0 Encoding errors
0 Number of requested variables
0 Number of altered variables
51550 Get-request PDUs
980 Get-next PDUs
0 Set-request PDUs
52530 SNMP packets output
0 Too big errors (Maximum packet size 1500)
714 No sUCh name errors
0 Bad values errors
0 General errors
52530 Response PDUs
0 Trap PDUs
SNMP logging: disabled
（2）Cisco 3550
3550#show snmp
Chassis: CAT0729X0KP
41669 SNMP packets input
0 Bad SNMP version errors
0 Unknown community name
0 Illegal operation for community name supplied
0 Encoding errors
56361 Number of requested variables
0 Number of altered variables
37800 Get-request PDUs
3869 Get-next PDUs
0 Set-request PDUs
41669 SNMP packets output
0 Too big errors (Maximum packet size 1500)
1 No such name errors
0 Bad values errors
0 General errors
41669 Response PDUs
0 Trap PDUs
SNMP global trap: disabled
SNMP logging: disabled
SNMP agent enabled

6.SNMP Community字符串密碼的修改
假如我們按照系統(tǒng)默認的密碼（即只讀的密碼為public，讀寫的密碼為private）的話，會帶來非常大的安全隱患，所以我們要修改密碼，在進行SNMP設置時，用自己定義的密碼。