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Ping works in the internet layer, but when I ping an IP address in my terminal, is ping in the application layer? If it is, how does the application pass transport layer?

If it is not, can I say those applications that use protocols in the application layer (SSH, DHCP, etc.) and pass the transport layer can be in the application layer not all applications?

Ron Maupin
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Sinoosh
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  • Ping is an application that uses ICMP, which is used like a transport-layer protocol, but is really an integral part of IP. – Ron Maupin Apr 07 '17 at 17:55
  • related : [why-is-the-icmp-protocol-considered-to-run-at-layer-3-on-the-wikipedia-page](http://networkengineering.stackexchange.com/questions/28707/why-is-the-icmp-protocol-considered-to-run-at-layer-3-on-the-wikipedia-page) – JFL Apr 07 '17 at 19:37
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer. – Ron Maupin Feb 19 '18 at 05:43

2 Answers2

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I'll start with the oft-repeated caveat (at least by me, anyway) that things don't fit neatly into the OSI model.

"Ping" is the name of an application that generates ICMP echo request packets and receives echo reply packets. ICMP doesn't neatly fit into the OSI or TCP/IP model, so you can call it layer 3 or layer 3.5, depending on your point of view.

Ron Trunk
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  • is it means the ping application is not in application layer? it use directly internet layer – Sinoosh Apr 07 '17 at 18:39
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    Ping is a program. Don't confuse it with the ICMP echo packets. You don't send a ping --you run the ping application that generates an ICMP packet. – Ron Trunk Apr 07 '17 at 19:09
  • i know that ping create icmp request and sends it and gets icmp reply.my question is about ping aplication not how to use ICMP.is this apllication run in the application layer? – Sinoosh Apr 07 '17 at 20:04
  • All applications run in the application layer- by definition. – Ron Trunk Apr 07 '17 at 20:59
  • So , Typically "ping" is implemented using "raw sockets" isn't it? – Sinoosh Apr 08 '17 at 06:33
  • That depends on the operating system and programming language- both of which are off topic here. – Ron Trunk Apr 08 '17 at 21:27
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Typically "ping" is implemented using "raw sockets". These let applications bypass the transport layer and generate/interpret packets themselves.

Raw sockets have security implications and hence there are often restrictions on them beyond those applied to regular sockets. Traditionally on unix-like systems ping was "suid" to allow it to use raw sockects through recent linux distros often use "capabilities" instead. I dunno what the picture looks like on other platforms.

Peter Green
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