ICMP Destination Unreachable messages - OmniSecu
www.omnisecu.com › tcpip › icmp-destinationHost 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: The packet cannot be fragmented and fragmentation is required as DF flag was set. 5: Source route failed
GitLab - code.fe80.eu
https://code.fe80.eu/openwrt/openwrt/-/issues/38815.01.2017 · From prod.lwn.net icmp_seq=920 Destination unreachable: Unknown code 5 64 bytes from prod.lwn.net: icmp_seq=921 ttl=50 time=81.1 ms 64 bytes from prod.lwn.net: icmp_seq=922 ttl=50 time=82.7 ms And it repeats about every 1-2 minutes. Believe me, having ipv6 working only 50-75% of the time is maddening!
5.2.7.1 Destination Unreachable - freesoft.org
www.freesoft.org › CIE › RFC5.2.7.1 Destination Unreachable. 5.2.7.1 Destination Unreachable. The ICMP Destination Unreachable message is sent by a router in response to a packet which it cannot forward because the destination (or next hop) is unreachable or a service is unavailable. Examples of such cases include a message addressed to a host which is not there and therefore does not respond to ARP requests, and messages addressed to network prefixes for which the router has no valid route.
ICMP type and code IDs
www.ibm.com › docs › enDestination 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: Communication with destination host is administratively prohibited: 11