NMAP 5.51 under CentOS 6.10 does not scan the host despite -Pn -Pn -PT1-65535 -PU1-65535 -v - how to force it?

Question

linux

Greetings.

Trying to scan a host via sudo nmap -Pn -PT1-65535 -PU1-65535 -v $HOST_IP

NMAP says that:

Nmap done: 1 IP address (0 hosts up) scanned in 0.48 seconds
Raw packets sent: 2 (56B) | Rcvd: 0 (0B)

But 2 packets is clearly not enough to perform a 131072 port scan.

Actually the question is - how to make NMAP scan regardless of any obstacles?

Answer 1

And in my opinion, you did not specify a single port.
Try like this:
sudo nmap -p- $HOST_IP

# nmap -v -p- 127.0.0.1

Starting Nmap 7.80 ( https://nmap.org ) at 2020-08-09 04:02 MSK
Initiating Parallel DNS resolution of 1 host. at 04:02
Completed Parallel DNS resolution of 1 host. at 04:02, 0.02s elapsed
Initiating SYN Stealth Scan at 04:02
Scanning 127.0.0.1 [65535 ports]
Discovered open port 22/tcp on 127.0.0.1
Completed SYN Stealth Scan at 04:02, 2.94s elapsed (65535 total ports)
Nmap scan report for 127.0.0.1
Host is up (0.000022s latency).
Not shown: 65534 closed ports
PORT   STATE SERVICE
22/tcp open  ssh

Read data files from: /usr/bin/../share/nmap
Nmap done: 1 IP address (1 host up) scanned in 3.16 seconds
           Raw packets sent: 65535 (2.884MB) | Rcvd: 131083 (5.506MB)