-5

I am using Try Hack Me to attempt to learn but they tell me to run nmap -A -p- and it is taking over an hour for a scan.

I am really new to this and want to know is there a faster way to perform a scan that shows open ports and os version?

Improve this question
5
  • 4
    man nmap has a ton of options. -T is what you're looking for. Commented May 31, 2021 at 19:04
  • 6
    It's always a good idea to add the full command you are running to your question. There's no way to know how big a network you are scanning, for example. Commented May 31, 2021 at 19:25
  • 1
    Expecting nmap to do fingerprinting and complaining about how long it takes is not logical. Commented May 31, 2021 at 19:48
  • 2
    Don't just follow instructions blindly from a website, find out what nmap -A -p xxxxx does before you try it. Commented Jun 1, 2021 at 1:59
  • fingerprinting is relatively fast, probing all ports most of which are dropping connections is quite slow. Commented Jun 1, 2021 at 13:56

1 Answer 1

Reset to default
0

As commenter @JeremyBoden wrote, "don't just follow instructions blindly from a website, find out what nmap -A -p xxxxx does before you try it".

The -A flag selects an Aggressive scan. This option is equivalent to -O -sV -sC --traceroute.

The -p- option scans all ports from 1 to 65535, as opposed to the Nmap default which scans only the most common ports. So it's normal that the command takes a long time.

You can run a faster scan by using the option -T4 or -T5, which use optimized parallelization. Please read the Nmap manual beforehand as these options are meant for high bandwidth networks. The Nmap default is -T3.

Improve this answer

You must log in to answer this question.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.