Unable to get SNMP info via Dhcpv4ServerSubnetFreeAddresses MIB

[Ro-Lak]

Hi Community 

A bit of context we currently use SNMP to pull DHCP info using the following MIBS. Use Prometheus -> SNMP_exporter - Grafana to visualise,

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/xe-16/dhcp-xe-16-book/dhcp-serv-mib.html 

• CISCO-IETF-DHCP-SERVER-MIB

• CISCO-IETF-DHCP-SERVER-EXT-MIBS

It works without issues, e.g if i use cDhcpv4ServerSubnetSharedNetworkName - I can see all the DHCP scopes..

however when I use cDhcpv4ServerSubnetFreeAddresses MIB - I can only see 4 out of the 6 scopes, On the cli I can see all the scopes and the leases. 

Thanks In advance.

[Georg Pauwen]

Hello,

tough one. First of all, I would check if the configured SNMP version (1/2/3) matches on the Cisco and the Prometheus side. That said, can you post your snmp.yml file ?

[Ro-Lak]

We use SNMPV3, and it's only this when scraping the cDhcpv4ServerSubnetFreeAddresses-MIB that i can't see all the DHCP leases. I can see all the DHCP scopes.

e.g

cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="10.x.30.x",cDhcpv4ServerSubnetSharedNetworkName="AWS1-5-Primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="10.x.31.x",cDhcpv4ServerSubnetSharedNetworkName="ASW1-1-primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="10.x.32.x",cDhcpv4ServerSubnetSharedNetworkName="ASW1-2-primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="10.x.33.x",cDhcpv4ServerSubnetSharedNetworkName="ASW1-3-primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="10.x.34.x",cDhcpv4ServerSubnetSharedNetworkName="asw1-4-primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="10.x.35.x",cDhcpv4ServerSubnetSharedNetworkName="ASW-LG-1-primary"} 1

cDhcpv4ServerSubnetFreeAddresses{cDhcpv4ServerSubnetAddress="10.x.30.0"} 137
cDhcpv4ServerSubnetFreeAddresses{cDhcpv4ServerSubnetAddress="10.x.33.0"} 139
cDhcpv4ServerSubnetFreeAddresses{cDhcpv4ServerSubnetAddress="10.x.34.0"} 138
cDhcpv4ServerSubnetFreeAddresses{cDhcpv4ServerSubnetAddress="10.x.35.0"} 115

Can't understand why I cannot see the below entires for cDhcpv4ServerSubnetFreeAddresses

10.x.32.x"
"10.x.31.x"

Thanks

[Ro-Lak]

Hi

SNMPV3 is been used, snmp.yaml seems to be correct. This is what i was referring to am not seeing all the scopes for  cDhcpv4ServerSubnetAddress.. can't figure out why.

cDhcpv4ServerSubnetFreeAddresses{cDhcpv4ServerSubnetAddress="x.x.30.0"} 137
cDhcpv4ServerSubnetFreeAddresses{cDhcpv4ServerSubnetAddress="x.x.33.0"} 139
cDhcpv4ServerSubnetFreeAddresses{cDhcpv4ServerSubnetAddress="x.x.34.0"} 138
cDhcpv4ServerSubnetFreeAddresses{cDhcpv4ServerSubnetAddress="x.x.35.0"} 115

cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="x.x.30.0",cDhcpv4ServerSubnetSharedNetworkName="AWS1-5-Primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="x.x.31.0",cDhcpv4ServerSubnetSharedNetworkName="ASW1-1-primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="x.x.32.0",cDhcpv4ServerSubnetSharedNetworkName="ASW1-2-primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="x.x.33.0",cDhcpv4ServerSubnetSharedNetworkName="ASW1-3-primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="x.x.34.0",cDhcpv4ServerSubnetSharedNetworkName="asw1-4-primary"} 1
cDhcpv4ServerSubnetSharedNetworkName{cDhcpv4ServerSubnetAddress="x.x.35.0",cDhcpv4ServerSubnetSharedNetworkName="ASW-LG-1-primary"} 1

Kind regards

Anuna