python中的漏洞扫描器代码不会生成任何输出

Question

我正在尝试连接到一系列ip地址和端口，并在收到的数据与任何横幅匹配时打印一条消息。

修复所有缩进错误后无法获得任何输出。 请看下面的代码：

import socket


def retBanner(ip,port):
    try:
        socket.setdefaulttimeout(280)
        s = socket.socket()
        s.connect((ip, port))
        banner = s.recv(1024)
        return banner
    except:
        return



def checkVulns(banner):
    if ('vsFTPd 3.0.3' in banner):
        print ('[+] vsFTPd Server is vulnerable.')
    elif '3Com 3CDaemon FTP Server Version 2.0' in banner:
        print('[+] 3CDaemon FTP Server is vulnerable.')
    elif 'Ability Server 2.34' in banner:
        print ('[+] Ability FTP Server is vulnerable.')
    elif 'Sami FTP Server 2.0.2' in banner:
        print('[+] Sami FTP Server is vulnerable.')
    else:
        print('[-] FTP Server is not vulnerable.')
    return




def main():
    portList = [21, 80]
    for x in range(68, 69):
        ip = '192.168.10.' + str(x)
        for port in portList:
            banner =retBanner(ip, port)
            if banner:
                print('[+]' + ip + ':' + str(banner))

if __name__=='__main__':
    main()