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internet Control Message Protocol (ICMP), documented in RFC 792, is a required protocol tightly integrated with IP. ICMP messages, delivered in IP packets, are used for out-of-band messages related to network operation or mis-operation. Of course, since ICMP uses IP, ICMP packet delivery is unreliable, so hosts can't count on receiving ICMP packets for any network problem. Some of ICMP's functions are to: * Announce network errors, such as a host or entire portion of the network being unreachable, due to some type of failure. A TCP or UDP packet directed at a port number with no receiver attached is also reported via ICMP. * Announce network congestion. When a router begins buffering too many packets, due to an inability to transmit them as fast as they are being received, it will generate ICMP Source Quenchmessages. Directed at the sender, these messages should cause the rate of packet transmission to be slowed. Of course, generating too many Source Quench messages would cause even more network congestion, so they are used sparingly. * Assist Troubleshooting. ICMP supports an Echo function, which just sends a packet on a round--trip between two hosts. Ping, a common network management tool, is based on this feature. Ping will transmit a series of packets, measuring average round--trip times and computing loss percentages. * Announce Timeouts. If an IP packet's TTL field drops to zero, the router discarding the packet will often generate an ICMP packet announcing this fact. TraceRoute is a tool which maps network routes by sending packets with small TTL values and watching the ICMP timeout announcements.
By far the most common use of icmp is ping.
What else can I help you with?
Which port is used by ICMP?
There really is no "port" for icmp but there is a icmp code. If you are looking for the icmp code for echo-reply it is 0 and the echo is 8 For an access list you could do the following: permit icmp any any echo-reply permit icmp any any echo Or the same using the icmp code permit icmp any any 0 permit icmp any any 8
Does a firewall block ICMP packets?
A firewall can be configured to block ICMP packets, but it depends on the specific rules set by the network administrator. By default, many firewalls allow ICMP traffic for essential functions like ping and network diagnostics. However, to enhance security, some firewalls may restrict or block certain types of ICMP packets to prevent potential attacks or network scanning. Ultimately, whether ICMP packets are blocked or allowed is determined by the firewall's configuration.
What port is used for icmp echo re quest?
There really is no "port" for icmp but there is a icmp code. If you are looking for the icmp code for echo-reply it is 0 and the echo is 8 For an access list you could do the following: permit icmp any any echo-reply permit icmp any any echo Or the same using the icmp code permit icmp any any 0 permit icmp any any 8
What port does icmp belong to?
ICMP does not have a port like TCP and UDP.
What is a ICMP packet?
Internet Control Message Protocol -ICMP provides maintenance and reporting functions. It's used by a PING program. When a user wasnts to test connectivity to another host, they can enter the PING command with the IP address, and the user's system will test connectivity to the other host's system. Routers and other network devices report path information between hosts with ICMP.
Why is it that an ICMP packet does not have source and destination port?
Because ICMP is on the network layer
Which ICMP message contain part of the ip datagram?
All ICMP Error Messages
Where the icmp request are originated?
icmp request is orginated on the OSI network layer with ip protocol.
Why filtering ICMP traffics by ACLs is not advised?
Because ICMP traffic, notably ICMP ECHO REQUEST-0 and ECHO REPLY-8 are used in network diagnostic sequences.
Which protocol should be allowed when not able to ping a remote device residing behind a firewall?
ICMP is the internet control access protocol . ICMP is the plrotocol that should be allowed when not able to ping a remote device residing behind a firewall. ICMP is the protocol of network layer.
What is the response if a host sends a ICMP to a default gateway?
If devices on a network are properly configured, a host sending ICMP to a default gateway must receive a reply. ICMP simply means ping.
What transport layer protocol does ping use?
Assuming IPv4 ICMP. Ping uses IP for transport. Ping in itself is an "Echo Request", which is a function of the ICMP protocol. The IP Packet will carry the ICMP protocol from end-to-end. ICMP has a protocol number of 1, so the "Protocol" field in the IPv4 header will contain "1" as a reference to the ICMP payload. For IPv6, ICMPv6 is used, and the transport will be IPv6.
