Re: Influence of pcap_open_live parameters on

[Doktor Bernd <doktorbernd () hotmail com>]

Hi, thanks for the answers,
 
the caveat of capturing the sent packets when capturing on the same interface is well known to me ;-)
So I defenitely use filtering on the capture interface (pcap_setdirection() is not always available)
 
All the best,
Bernd
 

 

> Subject: Re: [tcpdump-workers] Influence of pcap_open_live parameters on pcap_sendpacket
> From: guy () alum mit edu
> Date: Tue, 16 Aug 2011 09:34:37 -0700
> To: tcpdump-workers () lists tcpdump org
>
>
> On Aug 16, 2011, at 5:10 AM, Doktor Bernd wrote:
>
> > Two questions:
> > - Do the two pcap_open_live() calls influence the hardware in anyway and have side effects on each other or are 
> > they bound to the handle and I can rely on the parameters I give to be set?
>
> For LAN hardware, the "promisc" argument to pcap_open_live() affects whether the interface is put in promiscuous 
> mode; all handles will be in promiscuous mode if any are (or, for that matter, if any other process has turned on 
> promiscuous mode directly rather than through libpcap).
>
> > - Do the parameters influence pcap_sendpacket() in any way? From the documentation I assume that they are only for 
> > capturing from that interface.
>
> None of them should affect pcap_sendpacket() directly; perhaps running in promiscuous mode will, for example, cause 
> the network adapter to be busier, which might slow down its sending of packets to some degree.-
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