On Thu, Mar 28, 2002 at 09:23:41AM -0600, CARL.P.HIRSCH@sargentlundy.com wrote:
Yeah, the device I've got in my head is a 1U server with 4 (or more?) interfaces... not so much to simultaneously pull 400Mbps of bandwidth for analysis but rather to just have a interface going to each switch I might want to monitor and then span traffic to the Ethereal box. Given that I'm trying to attain remote visibility, it might be nice not to need remote hands to be swapping patch cords back and forth.
I'm imagining that even with a relatively speedy box, if you were trying to do analysis from multiple interfaces you'd at least choke the disk I/O. There's always stringent filters, I guess.
Disk I/O on a sniffer box? Sounds like you've been sniffing something other than packets my friend. :) You can build your own box like that easily enough. If you're going for FastE sniffing I highly recommend the Adaptec Quartet 4-port cards. If you're going for GigE sniffing, I STILL highly recommend anything Alteon Tigon 2 based (NetGear GA620's were the cheapest if you can still find them, not the 621/622). I've had great luck making the Tigon 2's into dedicated sniffers. You don't even have to do anything fancy with the card firmware, there is a native command for receiving only part of the frame. Check out the programming manuals at http://people.freebsd.org/~wpaul/Alteon/, and I recommend you use FreeBSD for this of course. Just add in a PARTIAL_RX_CNT command, and the card will only DMA part of the packet (say 64 bytes for full headers) across the PCI bus. Combined with interrupt coalescing (or luigi's device polling and tuning the card to allocate all memory to RX and remove the TX functionality completely), you can sniff quite a few "gigabits" of traffic on a single cheap PC server. You can dump it through the BPF mechanism and still maintain support for all your favorite sniffer programs. Or if you're comfortable writing kernel code, I recommend you make a character device for sniffer device control, and use it to pass page-aligned malloc'd memory pointers from userland into the nic driver, which you then pass to the card as the RX ring buffers. This will let you DMA your packets directly into userland. If not, at least unhook ether_input(). :) Or you can buy these things commercially. My favorite was from a company called Tekelec, who sold a VERY expensive box which turned out to be a pentium 200ish box running solaris x86 and completely useless sniffing software, with a bunch of ISA ethernet cards hooked up by proprietary (and VERY expensive) cables, all in a box made out of what I swear was some kind of lead/neutron star material alloy. Of course that was a couple years ago, maybe they've upgraded to the current market's $50 processor. :) -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras PGP Key ID: 0x138EA177 (67 29 D7 BC E8 18 3E DA B2 46 B3 D8 14 36 FE B6)