2023年12月15日 · Yesterday an interviewer asked me what the port number for ping is and which protocol ping uses: TCP or UDP. After the interview, I searched on the Internet and found different results: someone says ICMP uses port 7, someone says it does not use any port number, on one site I found it uses IP protocol 1, etc.

2018年11月2日 · ICMP doesn't have "port numbers" per-se, but it does have things that are similar to port numbers, and in some cases the ICMP payload will contain port numbers for other layer 4 protocols. All ICMP packets have a "type", this identifies the type of the ICMP package. The types of ICMP packet can be broadly divided into four categories: Errors ...

2017年9月25日 · UDP and TCP with target port 7 is also known as services "echo" (port 7) and "discard" (port 9). It may be a good idea to block this target ports in the firewall or disable that services on the target hosts (if not already done) or both.

2018年3月7日 · ICMP acts like a layer-4 protocol, but it is really an integral part of IP, a layer-3 protocol that knows nothing about port numbers. See RFC 792, INTERNET CONTROL MESSAGE PROTOCOL : ICMP, uses the basic support of IP as if it were a higher level protocol, however, ICMP is actually an integral part of IP, and must be implemented by every IP module.

• From the given image below, you can observe that instead of the ICMP protocol, the ping request has been sent through NBNS (NetBIOS Name Service) protocol through port 137 which is a UDP port. • By default, a ping sends 4 packets of the request and receives the same number of the packet as a reply from the host.

2021年4月17日 · Possible causes of ICMP Destination unreachble - Port unreachable. Ask Question Asked 4 years ago.

Here is a wireshark capture of the ICMP echo reply packets. As Ismael da Silva said, ICMP uses type value 0 and code value 0 for echo reply packets. Here is a thread that Peter Paluch explaining which transport protocol does ICMP uses.. OSPF and ICMP not use Transport protocol | WAN, Routing and Switching | Cisco Support Community | 5991 | 11610886

2019年10月11日 · Barring server S doing something (like sending an ICMP Destination Port Unreachable) or the application on C stopping this transfer for some reason, it will continue to send 3 TB of data to S. S must still receive (and then discard) all this data. The ICMP Destination Port Unreachable prevents the majority of this data from ever being sent.

ICMP (ping, trace)is a layer 3 protocol suite within the TCP/IP suite, doesnt test any layer 4 or above functions, therefore, it has no TCP/UDP layer 4 port number. The sub protocols within it do. You can block echo replies by closing port 7.

2018年5月14日 · The destination host MUST (if possible) add the current timestamp to a Timestamp option before passing the option to the transport layer or to ICMP for processing. A timestamp value MUST follow the rules given in Section 3.2.2.8 for the ICMP Timestamp message. and - 3.2.2.8 Timestamp and Timestamp Reply: RFC-792