1.9.3 Configure source interface for SNMP Traps

Information

The administrator can configure SNMP to the interfaces source IP address for notifications

By using a source interface the administrator can ensure that the source IP of SNMP traps does not change as the network topology changes. For instance, if a link fails or is reconfigured, and a different IP address is now topologically "closer" to the SNMP trap server.There are a few typical candidates for an SNMP source IP address:

- A loopback address, as loopbacks are always up, and can then route over any transit interface.
- The MGMT 0 address, as that provides an out-of-band path to the SNMP server. SNMP traffic volume will not affect traffic volumes, and SNMP cannot be "starved" for bandwidth by production traffic. If the entire path is out-of-band, this also provides excellent protection from eavesdropping by malicious actors that may be on the "production data side" of the switch.
- A combination of the two (this is less common) - for instance a loopback address in the management VRF

Solution

switch(config)# snmp-server host 1.2.3.4 source-interface mgmt 0

or

switch(config)# snmp-server host 1.2.3.4 source-interface loopback 0

SNMP Server traps or informs:

switch(config)# snmp-server source-interface traps loopback 0
switch(config)# snmp-server source-interface informs loopback 0

or

switch(config)# snmp-server source-interface traps mgmt 0
switch(config)# snmp-server source-interface informs mgmt 0

See Also

https://workbench.cisecurity.org/benchmarks/16139

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b.

Plugin: Cisco

Control ID: 408a26e672660abc4cdcc4a0e9b214f05ce73f5d2cf1d1388aba45021aef811c