Finger

Find Logged in users on target.

finger @$ip

Check User is existed or not.

finger USERNAME@$ip

finger-user-enum

cd /tmp/
wget http://pentestmonkey.net/tools/finger-user-enum/finger-user-enum-1.0.tar.gz
tar -xvf finger-user-enum-1.0.tar.gz
cd finger-user-enum-1.0
perl finger-user-enum.pl -t 10.22.1.11 -U /tmp/rockyou-top1000.txt