The meanings of flags in the Layer 2 view depend the pane in which they appear.
In the Filter and Endpoints panes, flags indicate the following:
![]() |
Switch-to-Switch connection - Connected to another switch |
![]() or ![]() |
Interior device - The device is attached to a hub or switch that is connected between ports of two managed switches. The left or right arrow points away from the spanning tree root. |
![]() |
Down - This port is not operating. |
![]() |
Multi-homed device - A single MAC address has multiple IP addresses. Each IP addresses is shown as a separate row in the Endpoints pane. |
![]() |
Ghost- Port is not active, and the endpoint (device with this MAC address) has not been seen elsewhere in the network. It was last seen on the indicated switch port. |
![]() |
Not present on Map - Port is connected to a managed switch, but that switch is not present on a Layer 2-enabled map. |
![]() or ![]() or ![]() |
Fuzzy - The Layer 2 process cannot determine the exact port where the device is attached. See Understanding Fuzzy Devices below. |
![]() |
Duplicate MAC address detected - The Layer 2 process has found the same MAC address on two separate switch ports. |
![]() |
IP conflict - The Layer 2 process has found the same IP address on two separate switch ports. |
![]() |
Spanning tree root - This switch is the root of the spanning tree. |
![]() |
Loop - a port is connected to another port on the same switch. |
![]() |
Wireless (assigned manually) - a port or VLAN has been tagged as Wireless. The Wireless flag appears next to the port in the Filters and Endpoints panes. See Manual Tagging below. |
![]() |
Virtual machine (assigned manually) - All NICs from this manufacturer with this OUI (organizationally unique identifier) are virtual machines. The Virtual Machine flag appears next to the OUI and any endpoints that use NICs with that OUI. See Manual Tagging below. |
The following flags may be present in the Flags column of the Connections pane.
![]() |
Confirmed connection - (will be exported to map). |
![]() or ![]() |
Not present on Map - Port is connected to a device that is not present on a Layer 2-enabled map. |
![]() |
Loop - Indicates a direct port-to-port connection on this switch |
![]() |
Both ends see each other's CDP/LLDP advertisements. |
![]() |
The left end of the connection sees the right end's CDP/LLDP advertisements. |
![]() |
The right end of the connection sees the left end's CDP/LLDP advertisements. |
![]() |
Connected to a device that is not present on any map. |
![]() |
Confirmed connection (will be exported to map). |
STP column: In the STP column of the Connections Pane, arrows indicate the direction of travel of STP bridge information.
![]() |
Right switch is the left switch’s path to root for one or more of the left switch’s spanning trees. (Right switch's port may be in blocking state, if there are loops.) |
![]() |
Left switch is the right switch’s path to root for one or more of the right switches’ spanning trees. (Left switch's port may be in blocking state, if there are loops.) |
![]() |
Right switch is left switch's path to root for one or more spanning trees and left switch is right switch's path to root for other spanning trees. (Either switch's port may be in blocking state for one or more spanning trees, if there are loops.) |
A device with a MAC address whose location in the Layer 2 topology cannot be completely determined is considered a “fuzzy” device by InterMapper.
Fuzzy devices are quite common, and can occur for a number of reasons. The Layer 2 engine attempts to collect information from all the switches nearly simultaneously. However, some time can elapse between the times that two switches finishes collecting Layer 2 information. During this time period, a MAC address collected from one switch may "age out" of another switch. Alternatively, a device may connect to the network during Layer 2 collection, so its MAC address is reported in one switch's forwarding tables, but not in the edge switch (due to the difference in scan times for the two switches).
Devices may be classified as fuzzy due to bugs in certain switch models. For example, Dartware has a small managed desktop switch that doesn't report its complete forwarding table via SNMP. The extra un-reported devices appear as fuzzy, because the upstream switch reports the MAC address, but the downstream switch never reports them (even though the switch is otherwise perfectly functional.)
Fuzzy devices are distinct from Interior devices. A fuzzy device appears to be in the middle of the network (between two switches) because InterMapper doesn't have complete information. An interior device appears to be in the middle of the network because there is actually another switch or hub located there, but it's not part of the Layer 2 information.
For certain kinds of connections, you may want to tag a port or endpoint device so you can see easily what kind of device it is.
Here are some tagging options:
![]() |
Wireless (assigned manually) - Right-click a switch port or VLAN in the Filters pane and select as Wireless from the Tag submenu. The Wireless icon appears next to the port or VLAN. |
![]() |
Virtual machine (assigned manually) - Right-click a port in the NIC manufacturer's section of the Filters pane (one that is associated with a virtual machine ), and select as Virtual Machine from the Tag submenu. The Virtual Machine icon appears next to the OUI and any endpoints that use NICs with that OUI. |