Re: Running multiple instances of tcpdump

[Guy Harris <guy () alum mit edu>]

Ravindranath, Chavalam wrote:

> When I tried a single instance of tcpdump, it worked fine, and I don't
> even have to specify the interface I want to monitor.
> When I left this first instance running and started another one, I got
> the message "tcpdump: no suitable device found". According to the
> information that I found on the Internet, this means that I need to
> specify the interface (why would it be required on the second instance).
> So I tried to specify the interface (lan0) and got a different message
> "tcpdump: recv_ack: promisc_phys: UNIX error - Invalid argument". Can
> you tell me why it worked like that?   

Because HP-UX doesn't support more than one process putting a particular 
interface into promiscuous mode at a time, so you can't have two 
instances of tcpdump (or any other application using promiscuous mode) 
running on the same interface at the same time.
-
This is the tcpdump-workers list.
Visit https://cod.sandelman.ca/ to unsubscribe.