Knock - Subdomain scan

Knock is a python script, written by Gianni Amato, designed to enumerate subdomains on a target domain through a wordlist.
Knock is targeted to:
-Scan subdomains
-DNS request for zone transfer
-DNS resolver
-Wildcard testing
-Wildcard bypass
For run we need python 2.x
You can download knock from here
For scan type :
./knock.py site.com
For scan with external wordlist type:
./knock.py site.com wordlist
Other options:
-zt : Zone Transfer discovery
-wc : Wildcard testing
-dns : Dns resolving
-bw : Bypass wildcard

If you have a problem or you need some explanations just write under this post!