nmap udp scan

I. Overview Task Description: Develop a program to obtain a list of host IP addresses for the SNMP service on the LAN and write the corresponding files for use by other programs. Background knowledge: SNMP is UDP-based, and the standard SNMP service uses 161 and 162 ports. Ideas: 1, get the local area online host list; 2, get the SNMP port of each host (for example, 161) to open the State; 3. Write specific files in a specific format. Only the first t

have UDP recvfrom scan, UDP ICMP Port unreachable scan, I used the latter, that is, to a port to send UDP packets, if the port is open, then there is no response, if the port is closed, The other side will reply to an ICMP Port unreachable message (corresponding to the firs

Because the UDP protocol is non-connection-oriented, the UDP port detection cannot depend on the connection establishment process as the TCP port detection (TCP protocol commands such as telnet cannot be used ), this also makes UDP port scanning less reliable. Therefore, although the UDP protocol is simpler than the TC