what do you mean by “network tap” ? like a physical wire splitter, or a linux box running tcpdump, or like, a jack in the wall to plug into for “internet” access?
edit:
this is a read-only ethernet cable, used to mirror one direction of a layer-2 ethernet session to a second network port:
I probably would anyway, because soldering on cat5 wires can really tank the SNR of the cable, whereas you could build the other in 5 minutes with a punchdown tool and 12" of cat5 solid core.
You’d have to be on the outside network edge of the router if you don’t trust the router, so if it’s ALSO your modem (ADSL/Fiber/Cable), then it’s a lot harder as a problem.
If you want a cheap enough way to do it otherwise, just grab a network switch that supports monitor/capture ports. Have a VLAN that just passes traffic between your modem & router, and also copies all traffic off the VLAN onto a monitor port that you can dump for analysis.
I have a little NetGear GS108Ev2 that I’ve used in the field for this explicit purpose, the only downside was having to use a Windows Vista VM to configure it in the first place. No VLAN, just dump all of ports 1-4 to port 8. Ports 5-7 pass traffic but don’t dump.
I was actually exactly thinking of the throwing star tap but I don’t have one and I wanted to deal with this sooner than I think I could get it shipped. And that being the case, I think I might avail myself of your offer.
Why would I need a USB NIC specifically? Do I need 2 because duplex?
You need two as each “side” of the tap reads one. Doesn’t need to be USB, anything with two networks.
I am heading out of town tonight, and won’t be back until tuesday, unfortunately. but I can bring it to VHS then.
Question for all of you:
If I have two NICs anyway and I’m not worried about reliability of the link couldn’t I invisibly MITM that traffic somehow? If so do you know how? My searchfoo is failing me.