Raw Sockets: Two Questions

[Michael Tuexen]

> 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?

Best regards
Michael
> 
>> 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.
> 
> 
> 
> _______________________________________________
> freebsd-net at freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-net
> To unsubscribe, send any mail to "freebsd-net-unsubscribe at freebsd.org"