the server did not show me the flag BUT
When i try using curl command
curl “http://165.227.106.113/post.php” -d “username=admin&password=71urlkufpsdnlkadsf”
Your requests seem fine. Just make sure that when you capture and send them to the Repeater, you check non-printable characters (\n). Each line in the response usually ends with \r\n , indicating a return followed by a new line, so keep that in mind.
HTTP/1.1 200 OK
Server: nginx/1.4.6 (Ubuntu)
Date: Thu, 02 May 2024 00:48:52 GMT
Content-Type: text/html
Connection: close
X-Powered-By: PHP/5.5.9-1ubuntu4.22
Content-Length: 118
<h1>This site takes POST data that you have not submitted!</h1><!-- username: admin | password: 71urlkufpsdnlkadsf -->