我正在使用 SNMP 轮询交换机以获取数据。我正在尝试检索 MAC 地址表 ( sho mac address-table) 以查看哪些设备连接到各个端口，但我似乎遇到了问题。在所有其他帖子、问题和指南中，普遍的共识是BRIDGE-MIB::dot1dTpFdbTable在该 MIB 中使用或使用另一个。无论出于何种原因，我都无法在我们的设备上使用此 OID。它总是吐槽“此 OID 的此代理上没有可用的此类对象”。

请求父对象snmpbulkwalk BRIDGE-MIB::dot1dBridge似乎提供设置和杂项。数据，但没有显示 MAC 条目。我们所有的设备（例如 C3750、C3850 和 C4506）都是如此。这是一些示例输出（C3560E，iOS 版本 c3560e-universalk9-mz.122-55.SE3）：

BRIDGE-MIB::dot1dBaseBridgeAddress.0 = STRING: 30:f7:d:4b:c8:0
BRIDGE-MIB::dot1dBaseNumPorts.0 = INTEGER: 6 ports
BRIDGE-MIB::dot1dBaseType.0 = INTEGER: transparent-only(2)
BRIDGE-MIB::dot1dBasePort.25 = INTEGER: 25
BRIDGE-MIB::dot1dBasePort.26 = INTEGER: 26
BRIDGE-MIB::dot1dBasePort.27 = INTEGER: 27
BRIDGE-MIB::dot1dBasePort.28 = INTEGER: 28
BRIDGE-MIB::dot1dBasePort.29 = INTEGER: 29
BRIDGE-MIB::dot1dBasePort.30 = INTEGER: 30
BRIDGE-MIB::dot1dBasePortIfIndex.25 = INTEGER: 10125
BRIDGE-MIB::dot1dBasePortIfIndex.26 = INTEGER: 10126
BRIDGE-MIB::dot1dBasePortIfIndex.27 = INTEGER: 10127
BRIDGE-MIB::dot1dBasePortIfIndex.28 = INTEGER: 10128
BRIDGE-MIB::dot1dBasePortIfIndex.29 = INTEGER: 10201
BRIDGE-MIB::dot1dBasePortIfIndex.30 = INTEGER: 10202
BRIDGE-MIB::dot1dBasePortCircuit.25 = OID: SNMPv2-SMI::zeroDotZero
BRIDGE-MIB::dot1dBasePortCircuit.26 = OID: SNMPv2-SMI::zeroDotZero
BRIDGE-MIB::dot1dBasePortCircuit.27 = OID: SNMPv2-SMI::zeroDotZero    
BRIDGE-MIB::dot1dBasePortCircuit.28 = OID: SNMPv2-SMI::zeroDotZero
BRIDGE-MIB::dot1dBasePortCircuit.29 = OID: SNMPv2-SMI::zeroDotZero
BRIDGE-MIB::dot1dBasePortCircuit.30 = OID: SNMPv2-SMI::zeroDotZero
BRIDGE-MIB::dot1dBasePortDelayExceededDiscards.25 = Counter32: 0
BRIDGE-MIB::dot1dBasePortDelayExceededDiscards.26 = Counter32: 0
BRIDGE-MIB::dot1dBasePortDelayExceededDiscards.27 = Counter32: 0
BRIDGE-MIB::dot1dBasePortDelayExceededDiscards.28 = Counter32: 0
BRIDGE-MIB::dot1dBasePortDelayExceededDiscards.29 = Counter32: 0
BRIDGE-MIB::dot1dBasePortDelayExceededDiscards.30 = Counter32: 0
BRIDGE-MIB::dot1dBasePortMtuExceededDiscards.25 = Counter32: 0
BRIDGE-MIB::dot1dBasePortMtuExceededDiscards.26 = Counter32: 0
BRIDGE-MIB::dot1dBasePortMtuExceededDiscards.27 = Counter32: 0
BRIDGE-MIB::dot1dBasePortMtuExceededDiscards.28 = Counter32: 0
BRIDGE-MIB::dot1dBasePortMtuExceededDiscards.29 = Counter32: 0
BRIDGE-MIB::dot1dBasePortMtuExceededDiscards.30 = Counter32: 0
BRIDGE-MIB::dot1dTpLearnedEntryDiscards.0 = Counter32: 0
BRIDGE-MIB::dot1dTpAgingTime.0 = INTEGER: 300 seconds
BRIDGE-MIB::dot1dTpPort.25 = INTEGER: 25 BRIDGE-MIB::dot1dTpPort.26 =
    INTEGER: 26 BRIDGE-MIB::dot1dTpPort.27 = INTEGER: 27
BRIDGE-MIB::dot1dTpPort.28 = INTEGER: 28 BRIDGE-MIB::dot1dTpPort.29 =
    INTEGER: 29 BRIDGE-MIB::dot1dTpPort.30 = INTEGER: 30
BRIDGE-MIB::dot1dTpPortMaxInfo.25 = INTEGER: 1510 bytes
BRIDGE-MIB::dot1dTpPortMaxInfo.26 = INTEGER: 1510 bytes
BRIDGE-MIB::dot1dTpPortMaxInfo.27 = INTEGER: 1510 bytes
BRIDGE-MIB::dot1dTpPortMaxInfo.28 = INTEGER: 1510 bytes
BRIDGE-MIB::dot1dTpPortMaxInfo.29 = INTEGER: 1510 bytes
BRIDGE-MIB::dot1dTpPortMaxInfo.30 = INTEGER: 1510 bytes
BRIDGE-MIB::dot1dTpPortInFrames.25 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInFrames.26 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInFrames.27 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInFrames.28 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInFrames.29 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInFrames.30 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortOutFrames.25 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortOutFrames.26 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortOutFrames.27 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortOutFrames.28 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortOutFrames.29 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortOutFrames.30 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInDiscards.25 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInDiscards.26 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInDiscards.27 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInDiscards.28 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInDiscards.29 = Counter32: 0 frames
BRIDGE-MIB::dot1dTpPortInDiscards.30 = Counter32: 0 frames

我知道交换机正在正确收集 MAC 地址，因为它通过 CLI 报告如下：

All    0100.0ccc.cccc    STATIC      CPU
All    0100.0ccc.cccd    STATIC      CPU
All    0180.c200.0000    STATIC      CPU
All    0180.c200.0001    STATIC      CPU
All    0180.c200.0002    STATIC      CPU
All    0180.c200.0003    STATIC      CPU
All    0180.c200.0004    STATIC      CPU
All    0180.c200.0005    STATIC      CPU
All    0180.c200.0006    STATIC      CPU
All    0180.c200.0007    STATIC      CPU
All    0180.c200.0008    STATIC      CPU
All    0180.c200.0009    STATIC      CPU
All    0180.c200.000a    STATIC      CPU
All    0180.c200.000b    STATIC      CPU
All    0180.c200.000c    STATIC      CPU
All    0180.c200.000d    STATIC      CPU
All    0180.c200.000e    STATIC      CPU
All    0180.c200.000f    STATIC      CPU
All    0180.c200.0010    STATIC      CPU
All    ffff.ffff.ffff    STATIC      CPU
100    001e.4a92.5c59    DYNAMIC     Gi0/24
100    0024.c33c.719d    DYNAMIC     Gi0/24
100    0024.c3a8.9c00    DYNAMIC     Gi0/24
100    b000.b4bf.9798    DYNAMIC     Gi0/24
200    0024.c33c.719d    DYNAMIC     Gi0/24
200    0024.c3a8.9c00    DYNAMIC     Gi0/24
500    0080.7752.bbb6    DYNAMIC     Gi0/1
200    2c27.d720.3e4d    DYNAMIC     Gi0/24
200    3417.eb98.f48e    DYNAMIC     Gi0/24
200    b8a3.8607.a6ef    DYNAMIC     Gi0/24
...

为了使数据可用，我需要添加配置中的设置吗？此 OID 是否已被弃用且不再可用？

解决方案

在其他位置显示的 SNMP 实现之一中省略了一个小细节。我没有认出它，但这可能是因为我对 SNMP 不够熟悉，或者因为它是多么微妙。

轮询BRIDGE-MIB::dot1dTpFdbTableOID 时，您必须将要查找的 VLAN 附加到社区字符串。我在解决方案中没有注意到这一点，因为通常所说的社区字符串是通用的。

例如：

snmpbulkwalk -v2c -cpublic hostname BRIDGE-MIB::dot1dTpFdbTable 将返回“此 OID 中当前不存在此类实例”

snmpbulkwalk -v2c -cpublic@vlan hostname BRIDGE-MIB::dot1dTpFdbTable将返回此 VLAN 内的所有 MAC 地址。注意添加的@vlan。