Ethereal-users: Re: [Ethereal-users] buffer length

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From: Guy Harris <gharris@xxxxxxxxx>
Date: Wed, 11 May 2005 12:16:07 -0700
rupesh gautam wrote:

i am using ethereal for studying packet drop in it. what is default buffer length ethereal uses.....and can we change buffer length by command line....if not then should i change in code and recompile it....

What do you mean by "buffer length"?

If you mean the buffer into which the packet capture mechanism in the kernel puts packets before the user-mode code in libpcap (as called by Ethereal) reads the packets, that's only configurable on Windows (because libpcap currently doesn't have an API to set it; one problem is that, on systems with BPF, such as the BSDs, you have to set the buffer size *before* binding a BPF device to an interface, meaning it can only be set at open time, and there's no argument to "pcap_open_live()" for that; this will probably be fixed in the future - there is no schedule for this).

So you can only change the buffer size on Windows, using the "-B" command line option.