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From: "Ronald F. Guilmette" <rfg@tristatelogic.com>
To: freebsd-net@freebsd.org
Subject: Re: Raw Sockets: Two Questions
In-Reply-To: <5AB1A9C5.9050707@grosbein.net>
Date: Wed, 21 Mar 2018 10:38:45 -0700
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In message <5AB1A9C5.9050707@grosbein.net>, 
Eugene Grosbein <eugen@grosbein.net> wrote:

>21.03.2018 3:09, Ronald F. Guilmette wrote:
>>  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.

Is it true for other *BSDs?

>> Second question:  If the above assertion is actually true, then how can
>> nmap manage to work so well on FreeBSD, despite what would appear to be
>> this insurmountable stumbling block (of not being able to receive replies)?
>
>nmap uses libdnet that provides some portability layer, including RAW socket operations.
>It uses bundled stripped-down version but we have "normal" one as net/libdnet port/package.
>You should consider using it too as convenience layer.

Thank you.  I will certainly look into this, however my needs are quite small
and modest... probably so modest that a "convenience layer" wouldn't be a
substantial help.