I should also add: if this is a *switch*, it won't necessarily see all its connected devices in its ARP table - unless it's running as a router, i.e. a pure layer 3 configuration.
To see the connected devices on a layer 2 switch you need the 802.1d bridge forwarding table, BRIDGE-MIB::dot1dTpFdbTable (1.3.6.1.2.1.17.4.3), or the VLAN-aware multiple tables in Q-BRIDGE-MIB::dot1qFdbTable / dot1qTpFdbTable On Thursday, 2 November 2023 at 08:07:21 UTC Brian Candler wrote: > atTable (1.3.6.1.2.1.3.1 > <https://www.alvestrand.no/objectid/1.3.6.1.2.1.3.1.html>) contains > atEntry rows (1.3.6.1.2.1.3.1.1 > <https://www.alvestrand.no/objectid/1.3.6.1.2.1.3.1.1.html>), each of > which has three columns, one of which is atIfIndex (1.3.6.1.2.1.3.1.1.1 > <https://www.alvestrand.no/objectid/1.3.6.1.2.1.3.1.1.1.html>). The > description of atIfIndex says: > > *"The interface on which this entry's equivalence is effective. The > interface identified by a particular value of this index is the same > interface as identified by the same value of ifIndex." * > > Therefore, if you're not seeing this, it's probably a problem with your > snmp generator configuration. Can you show your generator.yml, and give an > example of the metrics you are getting? > > Aside: atTable is ancient and deprecated since 1991 (MIB-II). If your > device supports one of the newer MIBs like ipNetToMediaTable > (1.3.6.1.2.1.4.22, RFC 1213) or ipNetToPhysicalTable (1.3.6.1.2.1.4.35, RFC > 4293), you should use that instead. > > Note that these tables contain the MAC addresses of *other* devices on > your network. If you want the MAC address *of the interface itself*, then > there is ifPhysAddress from the ifTable (which is collected with the > out-of-the-box SNMP generator config). > > # HELP ifPhysAddress The interface's address at its protocol sub-layer - > 1.3.6.1.2.1.2.2.1.6 > # TYPE ifPhysAddress gauge > ifPhysAddress{ifAlias="",ifDescr="ether1",ifIndex="1",ifName="ether1",ifPhysAddress="00:5A:FF:1C:79:FD"} > > 1 > > On Wednesday, 1 November 2023 at 20:24:39 UTC Tyler Mace wrote: > >> I am using a cisco_wlc switch with snmp-exporter. >> >> The SNMP service knows about the connected MAC addresses for each port >> (through it's ARP table). Every other field for network metrics uses >> ifIndex as an index input. But this index doesn't work for the >> atPhysAddress OID. How can I correlate the ifIndex to the atPhysAddress to >> dynamically get MAC addresses? >> > -- You received this message because you are subscribed to the Google Groups "Prometheus Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/prometheus-users/ae03b5b4-8c5e-4a31-9aa1-572c7a9ddd37n%40googlegroups.com.
