The administrator can configure SNMP to the interfaces source IP address for notifications Rationale: 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 Default Value: Not configured. By default SNMP traffic is sourced from the layer 3 interface that is topologically closest to the configured SNMP server