subfinder: add page (#2178)

pages/common/subfinder.md

@@ -0,0 +1,24 @@
+# subfinder
+
+> A subdomain discovery tool that discovers valid subdomains for websites.
+> Designed as a passive framework to be useful for bug bounties and safe for penetration testing.
+
+- Find subdomains for a specific domain:
+
+`subfinder -d {{example.com}}`
+
+- Show only the subdomains found:
+
+`subfinder --silent -d {{example.com}}`
+
+- Use bruteforcing to find subdomains:
+
+`subfinder -d {{example.com}} -b`
+
+- Remove wildcard subdomains:
+
+`subfinder -nW -d {{example.com}}`
+
+- Use a given comma-separated list of resolvers:
+
+`subfinder -r {{8.8.8.8}},{{1.1.1.1}} -d {{example.com}}`