инструмент исследования сети и сканер безопасности / портов (Network exploration tool and security / port scanner)
Описание (Description)
Nmap ('Network Mapper') is an open source tool for network
exploration and security auditing. It was designed to rapidly
scan large networks, although it works fine against single hosts.
Nmap uses raw IP packets in novel ways to determine what hosts
are available on the network, what services (application name and
version) those hosts are offering, what operating systems (and OS
versions) they are running, what type of packet filters/firewalls
are in use, and dozens of other characteristics. While Nmap is
commonly used for security audits, many systems and network
administrators find it useful for routine tasks such as network
inventory, managing service upgrade schedules, and monitoring
host or service uptime.
The output from Nmap is a list of scanned targets, with
supplemental information on each depending on the options used.
Key among that information is the 'interesting ports table'.
That table lists the port number and protocol, service name, and
state. The state is either open, filtered, closed, or unfiltered.
Open means that an application on the target machine is listening
for connections/packets on that port. Filtered means that a
firewall, filter, or other network obstacle is blocking the port
so that Nmap cannot tell whether it is open or closed. Closed
ports have no application listening on them, though they could
open up at any time. Ports are classified as unfiltered when they
are responsive to Nmap's probes, but Nmap cannot determine
whether they are open or closed. Nmap reports the state
combinations open|filtered and closed|filtered when it cannot
determine which of the two states describe a port. The port table
may also include software version details when version detection
has been requested. When an IP protocol scan is requested (-sO),
Nmap provides information on supported IP protocols rather than
listening ports.
In addition to the interesting ports table, Nmap can provide
further information on targets, including reverse DNS names,
operating system guesses, device types, and MAC addresses.
A typical Nmap scan is shown in Example 1. The only Nmap
arguments used in this example are -A, to enable OS and version
detection, script scanning, and traceroute; -T4 for faster
execution; and then the hostname.
Example 1. A representative Nmap scan
# nmap -A -T4 scanme.nmap.org
Nmap scan report for scanme.nmap.org (74.207.244.221)
Host is up (0.029s latency).
rDNS record for 74.207.244.221: li86-221.members.linode.com
Not shown: 995 closed ports
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 5.3p1 Debian 3ubuntu7 (protocol 2.0)
| ssh-hostkey: 1024 8d:60:f1:7c:ca:b7:3d:0a:d6:67:54:9d:69:d9:b9:dd (DSA)
|_2048 79:f8:09:ac:d4:e2:32:42:10:49:d3:bd:20:82:85:ec (RSA)
80/tcp open http Apache httpd 2.2.14 ((Ubuntu))
|_http-title: Go ahead and ScanMe!
646/tcp filtered ldp
1720/tcp filtered H.323/Q.931
9929/tcp open nping-echo Nping echo
Device type: general purpose
Running: Linux 2.6.X
OS CPE: cpe:/o:linux:linux_kernel:2.6.39
OS details: Linux 2.6.39
Network Distance: 11 hops
Service Info: OS: Linux; CPE: cpe:/o:linux:kernel
TRACEROUTE (using port 53/tcp)
HOP RTT ADDRESS
[Cut first 10 hops for brevity]
11 17.65 ms li86-221.members.linode.com (74.207.244.221)
Nmap done: 1 IP address (1 host up) scanned in 14.40 seconds
The newest version of Nmap can be obtained from https://nmap.org https://nmap.org/book/man.html https://nmap.org/book/
