## IP Protocol scanning (-sO)

IP protocol scanning enables the determination of supported IP protocols (such as TCP, ICMP, IGMP, etc.) on target machines. Technically speaking, this is not port scanning, as it examines IP protocol numbers rather than TCP or UDP port numbers. Protocol scanning works in the same way as UDP scanning. Instead of iterating through the UDP packet's port number field, it sends the headers of an IP packet and iterates through the eight-bit IP protocol field. The headers are usually empty and do not contain any data or even the correct header for the claimed protocol. Certain popular protocols (including TCP, UDP, and ICMP) are exceptions. The correct protocol headers are included for them, as otherwise some systems would not respond to them.

In basic devices (computer, phone, etc.), usually only TCP, UDP, ICMP, and (sometimes) IGMP are open, while routers often offer much more, including routing protocols such as GRE and EGP. Firewalls and VPN gateways, on the other hand, may display encryption protocols such as IPsec and SWIPE.

```sh
sudo nmap -sO 192.168.1.1
Password:
Starting Nmap 7.91 ( https://nmap.org ) at 2023-07-13 19:31 EEST
Stats: 0:00:26 elapsed; 0 hosts completed (1 up), 1 undergoing IPProto Scan
IPProto Scan Timing: About 34.49% done; ETC: 19:32 (0:00:51 remaining)
Stats: 0:02:15 elapsed; 0 hosts completed (1 up), 1 undergoing IPProto Scan
IPProto Scan Timing: About 67.05% done; ETC: 19:34 (0:01:06 remaining)
Nmap scan report for 192.168.1.1
Host is up (0.0076s latency).
Not shown: 245 closed Protocols
PROTOCOL STATE SERVICE
1 open icmp
2 open|filtered igmp
4 open|filtered ipv4
6 open tcp
17 open udp
41 open|filtered ipv6
47 open|filtered gre
50 open|filtered esp
51 open|filtered ah
136 open|filtered udplite
255 open|filtered unknown
MAC Address: AC:15:A2:49:D3:34 (Unknown)

Nmap done: 1 IP address (1 host up) scanned in 309.11 seconds

```

@exercise c8327ae930a7

@exercise d1ec5b82fac3


IP Protocol scanning

IP Protocol scan

Nmap is one of the most well-known tools that you can use to perform versatile network scans. Every information security professional should know how to use this tool.

Nmap is one of the most well-known network scanning tools, often used by cybersecurity experts. In this course, we will learn how to use this tool and explore its capabilities. Additionally, we will examine the traffic generated by the tool and analyze the pros and cons of different scanning methods. It is beneficial to have an understanding of how networks operate in this course.

Warning! - Conducting network scans without permission may cause system malfunctions and/or crashes. Please refrain from attempting to scan any address/system without certainty that said system is in your possession or that you have permission to do so.

Computer Networks

What is Nmap?

Nmap installation on your own workstation (optional)

Intro

Defining the destination

Detection of hosts

Host discovery techniques

Finding hosts

Introduction to port scanning

Saving the output and determining the resolution of the output

Configuring ports

Choices related to timing

IPv6 scanning

Port scanning - overview

TCP SYN scan

TCP connect scan

UDP scan

TCP FIN, NULL and Xmas scan

TCP ACK scan

Port scanning techniques

Identification of services (-sV)

Identification of services and operating system

An introduction to Nmap scripts

Nmap scripts

Nmap

IP Protocol scan

Learn to hack — start here