ICMP - Destination Unreachable Message Analysis
www.firewall.cx › networking-topics › protocolsJan 07, 2022 · The ICMP - Destination host unreachable message is one which a user would usually get from the remote gateway when the destination host is unreachable. If, in the destination host, the IP module cannot deliver the packet because the indicated protocol module or process port is not active, the destination host may send an ICMP destination protocol / port unreachable message to the source host.
ICMP type and code IDs
www.ibm.com › docs › enICMP Type 3: Destination Unreachable Codes; Destination Unreachable Code Description; 0: Net is unreachable: 1: Host is unreachable: 2: Protocol is unreachable: 3: Port is unreachable: 4: Fragmentation is needed and Don't Fragment was set: 5: Source route failed: 6: Destination network is unknown: 7: Destination host is unknown: 8: Source host is isolated: 9: Communication with destination network is administratively prohibited: 10
ICMP Destination Unreachable messages - OmniSecu
www.omnisecu.com › tcpip › icmp-destinationICMP Code Meaning Description; 0: Net Unreachable: The destination network could not be found. 1: Host Unreachable: The destination network is available, but the destination computer was not. The destination computer may be down. 2: Protocol Unreachable: Specified protocol is invalid. 3: Port unreachable: Specified port is invalid. 4: Fragmentation Needed, and DF flag was set