Discovery | SNMP Devices Are Scanned by Shazzam When Use SNMP Version Is Set to All, but Are Not Scanned When Set to v1/v2c<!-- /*NS Branding Styles*/ --> .ns-kb-css-body-editor-container { p { font-size: 12pt; font-family: Lato; color: #000000; } span { font-size: 12pt; font-family: Lato; color: #000000; } h2 { font-size: 24pt; font-family: Lato; color: black; } h3 { font-size: 18pt; font-family: Lato; color: black; } h4 { font-size: 14pt; font-family: Lato; color: black; } a { font-size: 12pt; font-family: Lato; color: #00718F; } a:hover { font-size: 12pt; color: #024F69; } a:target { font-size: 12pt; color: #032D42; } a:visited { font-size: 12pt; color: #00718f; } ul { font-size: 12pt; font-family: Lato; } li { font-size: 12pt; font-family: Lato; } img { display: ; max-width: ; width: ; height: ; } } Issue Shazzam is not finding SNMP Port 161 open for some devices when Use SNMP Version is set to v1/v2c on a Discovery Schedule. Symptoms • Shazzam finds SNMP Port 161 open on the same devices when Use SNMP Version is set to All on the Discovery Schedule. • Working Credentials for the devices are SNMP v1/v2 community string credentials. Facts • Since SNMP is a stateless UDP protocol Shazzam tests if Port 161 is open by sending an SNMP OID request to the device. The device needs only to reply to the request regardless of whether it failed or not. If it replies, then the port is found to be open. • When Use SNMP Version is set to All on the Discovery Schedule Shazzam sends separate SNMP v1/v2c GetNext and SNMP v3 GetNext requests. • When Use SNMP Version is set to v1/v2c on the Discovery Schedule Shazzam sends just a SNMP v1/v2c GetNext request. • Some SNMP devices can be configured to not reply to SNMP GetNext requests over SNMP v1/v2c and will only reply to GetBulk or GetScalar SNMP requests. Release All Cause The SNMP device is configured to not reply to GetNext requests over SNMP v1/v2c, but does reply to GetNext requests over SNMP v3. Resolution Whether the Use SNMP Version field is set to v1/v2c or All, the SNMP - Classify probe triggered after Shazzam will test SNMP Credentials using GetNext and the device will fail to be classified. • The SNMP device will need to be configured to reply to GetNext requests over SNMP v1/v2c. * An alternate solution is to configure SNMPv3 credentials for the device. ServiceNow Product Documentation SNMP support for Discovery SNMP Probes