tcpdump - making the network run smoother

[linuxtricks]

Apparently, tcpdump is able to change some settings on an interface in order to monitor traffic, i.e. it sets it to "promiscuous mode" (allowing packets from any source?).

I guess the changes must be temporary. Anyway, whenever I run tcpdump on a LAN, it seems to allow traffic to pass much quicker than in normal mode. So I figured something the program temporarily reconfigures is making the network run smoother. If I could figure out what it was I would make the change permanent.

Any ideas? ---
Try not. Do. Or do not. There is no try.

 

[ifincham]

Hi,



Not sure that sounds very logical - anyway, you can put an interface into promiscuous mode like this :



/sbin/ifconfig eth0 promisc



to revert do :



/sbin/ifconfig eth0 -promisc


Promiscuous mode means that the adapter grabs all frames rather than just those addressed to its mac address. Thats how you can see everything that passes thru your machine and, if you're in a non switched environment, thats everything on the lan segment.


Regards