You will need to find the MAC that was learned on the port.
show mac-address interface fa0/18
On the device that provides the layer 3 for that VLAN, ping the broadcast address, then do a show arp | inc [the learned MAC]. That will provide the IP address.
Hope that helps.
Example-
ABC-SAL-16-1#sh mac-add interface gi0/1
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
616 00a0.b816.09f9 DYNAMIC Gi0/1
ABC-SDL-34-1#ping 10.10.16.255
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.16.255, timeout is 2 seconds:
Reply to request 0 from 10.10.16.252, 24 ms
Reply to request 0 from 10.10.16.243, 24 ms
Reply to request 0 from 10.10.16.242, 24 ms
Reply to request 0 from 10.10.16.241, 24 ms
Reply to request 0 from 10.10.16.240, 24 ms
Reply to request 1 from 10.10.16.243, 1 ms
Reply to request 1 from 10.10.16.252, 1 ms
Reply to request 1 from 10.10.16.241, 1 ms
Reply to request 1 from 10.10.16.240, 1 ms
RKB-SDL-34-1#sh arp | inc 00a0.b816.09f9
Internet 10.10.16.240 0 00a0.b816.09f9 ARPA Vlan616
I'm assuming once you know the IP, you can figure out the hostname/netbios name/etc.
Hope that helps
