Raw Sockets: Two Questions

[Eugene Grosbein]

On 21.03.2018 08:03, Michael Tuexen wrote:

>> On 21. Mar 2018, at 00:39, Eugene Grosbein <eugen at grosbein.net> wrote:
>>
>> 21.03.2018 3:09, Ronald F. Guilmette wrote:
>>
>>> I'm going to be doing some stuff with raw sockets pretty soon, and
>>> while scrounging around, looking for some nice coding examples, I
>>> found the following very curious comment on one particular message
>>> board:
>>>
>>>    https://stackoverflow.com/questions/7048448/raw-sockets-on-bsd-operating-systems
>>>
>>>      "Using raw sockets isn't hard but it's not entirely portable. For
>>>      instance, both in BSD and in Linux you can send whatever you want,
>>>      but in BSD you can't receive anything that has a handler (like TCP
>>>      and UDP)."
>>>
>>> So, first question:  Is the above comment actually true & accurate?
>>
>> Not for FreeBSD.
> Are you saying that I can receive on a raw socket SCTP, TCP and UDP packets?

No. I'm saying one can send/receive RAW IP packets no matter are they SCTP, TCP or UDP
or something else by means of libdnet. It uses raw sockets and BPF internally
but hides this complexity. nmap uses it just fine.