If you get no response from the switch, you will see
no rows or columns populated in the grid and a timeout
message will appear. Check to make sure the switch has
SNMP enabled and verify that the access credentials you
have for reading information from the switch is correct.
If your switch has a permitted IP list or Access Control
List (ACL), you may need to add your IP address to that
list. Make sure your computer's personal firewall is
allowing UDP traffic on port 161 to travel BOTH ways.
You are not seeing IP addresses associated with the
MAC addresses. You need to put a device like a file
server or router (running SNMP) into the Server/Router 1
or 2 so you can access the device's ARP table. The
device(s) need to have visibility into the local area
network served by the switch. This table is required to
match MAC addresses to IP addresses. More information on
this problem can be found on this
If you have
a Cisco switch and you are using SNMPv1 or v2c and get
nothing but an error at the beginning of the mapping,
make sure the switch has SNMP enabled. You will need to
use CLI and
follow these instructions for enabling it.
you have a Dell switch and the MAC address/IP
address/Hostname/Interface columns are blank, you
probably have an older switch operating system that
needs to be updated from Dell's support website.