quick wireshark question

nomb · 10-12-2007, 12:01 PM

Hey guys,

I was trying to troubleshoot a connection problem I was having the other day. I was using wireshark from my wireless laptop, trying to see the packets my hardwired desktop was putting out. However, when I was connected via wifi, I couldn't see the traffic going through the router unless it was from my own laptop. When I connected it through a rj-45 cable, I could. Is it suppose to be like that?

nomb

gschlais · 10-12-2007, 12:54 PM

I may be wrong, but I don't believe most wireless drivers allow you to place the wireless NIC into promiscuous mode. That would account for you not being able to see any packets that weren’t meant for your system.

farslayer · 10-12-2007, 02:34 PM

Ethernet switches do NOT replicate all traffic on all ports, otherwise we would all still be using Hubs.
The only thing you should see when sniffing a switched network is brodcast traffic, unless you enable a SPAN port on the switch.

dsniff might work from your wireless connection however to sniff that traffic. It can be used to sniff switched network traffic...

unixfool · 10-13-2007, 11:24 PM

Quote:

Originally Posted by farslayer

Ethernet switches do NOT replicate all traffic on all ports, otherwise we would all still be using Hubs.
The only thing you should see when sniffing a switched network is brodcast traffic, unless you enable a SPAN port on the switch.

dsniff might work from your wireless connection however to sniff that traffic. It can be used to sniff switched network traffic...

Keep in mind that hubs are still being manufactured and used.

I use a hub on my LAN and I use it specifically to monitor my Windows hosts. I'm not about to go out and buy an expensive piece of equipment that has a SPAN port when I can use a hub.

Also, ethernet taps usually work OK, also. In fact, they work better than hubs, since you don't have to worry about throughput degradation as much (although it theoretically won't matter to someone with a cable connection...but I've FIOS

).

nomb · 10-16-2007, 11:13 PM

When I compiled my wifi drivers I included the ability to go into 'monitor' mode, however when you are in monitor mode, I don't know if you can limit it to one network and an encrypted one at that.

nomb