[NTLUG:Discuss] promiscuous mode...

[Kyle_Davenport@compusa.com]

hmmm.  I noticed my DEC tulip chip card was in promiscuous mode before, but I
thought that was normal.  Reading doc's it seems like a question of packet
filtering in hardware or software, so I really don't see why that would affect
your throughput.
I can change the promiscuous flag without a problem (ifconfig eth0 shows PROMISC
gone)

in the ethernet-HOWTO, Donald Becker implied that some cards cannot do hardware
filtering and will always be in promiscuous mode.





MadHat <madhat at unspecific.com> on 04/10/2000 11:22:46 AM

Please respond to discuss at ntlug.org

To:   NT LUG <discuss at ntlug.org>
cc:    (bcc: Kyle Davenport/Is/Corporate/CompUSA)
Subject:  [NTLUG:Discuss] promiscuous mode...




So I am sitting  here at my desk trying to get to a site, and it is dog
slow...  I look and don't see anything odd, so I try to hit it from
another box on my desk and it is fast, so I do some more research...
turns out that my NIC is set in promiscuous mode and receiving all
packets broadcasted on my network...  It is averaging 450+kbits/sec...
This is rather anoying.

I have tryed

from 'man ifconfig'
" [-]promisc
              Enable  or  disable  the  promiscuous  mode  of the
              interface.  If selected, all packets on the network
              will be received by the interface."

# ifconfig eth0 -promisc
which should disable promiscuous mode, but didn't seem to change
anything.  While watching the packets come throgh, I can see that 99% of
them are not for me, so I am still in promiscuous mode....  any ideas on
how to disable promiscuous mode temporarily (I do have to use it from
time to time for my job).

I am running:
# uname -a
Linux madhat.broadcast.com 2.2.12 #9 Fri Oct 29 22:31:53 CDT 1999 i686
unknown

# ifconfig -V
net-tools 1.51
ifconfig 1.39 (1999-03-18)

pcmcia-cs-3.0.12
 3Com 3CCFE575 Cyclone CardBus

TIA for any ideas.

BTW, I don't want to have to disable it in the kernel, but will if
necessary.  I know this is an option.