The destination port specified in the UDP or TCP header was invalid or does not exist on the destination host. Note that Code value 2 is not used. Also, Destination Unreachable messages are only sent when there is a fundamental problem with delivering a particular datagram; they are not sent when a datagram is dropped simply due to congestion
Destination Host Unreachable - OpenVPN Support Forum Sep 28, 2015 What is ICMP? The Internet Control Message Protocol Explained Jun 08, 2020 ネットワーク入門サイト - ICMP destination unreachableはトラブルでパケットを採取するとよく見るICMPです。 コード0のnetwork unreachableは途中のルーターまでは届いておりルーティングテーブルにも載っていますが、例として宛先まで届ける事が出来ない時に使われます。
Icmp error - destination unreachable (port unreachable
ICMP Unreachable - Engineer Life Nov 09, 2016 ICMP destination unreachable to DNS server? - Wireshark Q&A After expiration of that timeout the client unbinds from the socket, causing icmp destination unreachable to be sent in response to anything arriving to that socket, including a valid DNS response. If you are interested in details, you can create a batch file like. @echo off for /l %%x in (1, 1, 60) do ( echo %%x netstat -p udp timeout 1 )
PROTOCOL-ICMP destination unreachable port unreachable packet detected. Rule Explanation.
ICMP Attacks - Infosec Resources