ICMP

1. Title:
Internet Control Message
Protocol
Submitted by:
Liva Un Noor [T3453]
Saurabh Jawarkar[T3452]
Rekha Kambale[T3454]
G. S. Mandal’s
Maharashtra Institute of Technology, Aurangabad
(An Autonomous Institute)
Department of Electronics and Computer Engineering
Academic year 2023-24

2. Introduction
●Definition: ICMP is a network protocol used to send
error messages and operational information indicating
problems with a network.
●Purpose: It helps in diagnosing network issues and
notifying users of errors.
●ICMP messages are encapsulated within IP packets,
providing a means for devices to communicate network-
layer information.

3. ICMP Basics
●Core Function: ICMP operates at the network layer of the OSI
model.
●Key Characteristics: It does not carry data like TCP or UDP, but
rather control and error messages.
●Relationship with IP: ICMP is closely tied to the Internet Protocol
(IP) and is used by routers, hosts, and network devices.

4. ICMP
Message
Types
●Echo Request/Reply: Used for network diagnostics, commonly
known as 'ping'.
●Destination Unreachable: Indicates that a packet cannot be
delivered.
●Time Exceeded: Indicates that a packet's TTL (Time-To-Live) has
expired.
●Redirect: Instructs a host to send packets through a different route.

5. ICMP Error
Messages
●ICMP plays a crucial role in reporting errors in network
communication.
●Examples: Host Unreachable, Port Unreachable, Protocol
Unreachable.
●Host Unreachable: The destination host is unreachable from the
sender.
●Port Unreachable: The port specified in the packet is not available
on the destination host.
●Protocol Unreachable: The protocol specified in the packet is not
supported on the destination host.
●Fragmentation Needed: The packet needs to be fragmented but the
'Don't Fragment' flag is set.

6. ICMP Security
Considerations
●Ping of Death: Exploiting vulnerabilities in the ICMP protocol to
launch Denial of Service (DoS) attacks.
●ICMP Redirect Attacks: Manipulating routing tables of hosts on a
network.

7. ICMP in
Network
Troubleshootin
g
●Ping: Used to test connectivity between two hosts.
●Traceroute: Utilizes ICMP Time Exceeded messages to identify the
route packets take to reach a destination.
●Path MTU Discovery: ICMP messages help determine the
Maximum Transmission Unit (MTU) size along a path.

8. ICMP Version
Differences
●ICMPv4 vs ICMPv6: While both versions serve similar purposes,
ICMPv6 introduces enhancements to support IPv6.
●Neighbour Discovery Protocol: A replacement for ARP in IPv6
networks, heavily reliant on ICMPv6.

9. ICMP and
Firewalls
●Firewall Considerations: ICMP traffic can be restricted or
filtered by firewalls.
●Blocking ICMP: While blocking ICMP may enhance
security, it can also hinder network troubleshooting and
diagnostic capabilities.
●Blocking ICMP: Some firewalls block ICMP traffic by
default due to security concerns.
●Commonly Blocked Types: ICMP Echo Requests (ping) and
ICMP Redirects.
●Impact of Blocking: Blocking ICMP may hinder certain
network diagnostic tools and troubleshooting capabilities.
●Best Practices: Instead of blanket blocking, selectively allow
specific ICMP types necessary for network operations while
blocking potentially harmful ones.

10. Conclusion
●ICMP is a fundamental component of the Internet Protocol
Suite, facilitating crucial communication between network
devices.
●Through ICMP, devices can exchange error messages,
diagnose network issues, and optimize routing decisions.
●Understanding ICMP is essential for network administrators,
enabling efficient troubleshooting and maintenance of
network infrastructures.
●While ICMP serves critical functions in network operations,
it's also important to implement security measures to mitigate
potential risks, such as ICMP-based attacks.
●In conclusion, ICMP plays a pivotal role in the functioning
and management of modern networks, underscoring the
significance of continued awareness and utilization in
network administration and security practices.

11. Thank you