How to disable promiscuous mode on nics?

[bassocksky]

Hello to the forum,

I just hit on a small problem on nics with the PROMISC flag set:
I'm not able to delete the flag with ifconfig.
In Linux and FreeBSD it is possible.

(I don't think of bridge configurations here....)

Some nics have the flag set:
em1: flags=8b43<UP,BROADCAST,RUNNING,PROMISC,ALLMULTI,S IMPLEX,MULTICAST> mtu 1500
...

and some not:
bge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
...

The flag for bge0 changes whem I'm running tcpdump:
bge0: flags=8b43<UP,BROADCAST,RUNNING,PROMISC,ALLMULTI,S IMPLEX,MULTICAST> mtu 1500
...

and is cleared if I stop tcpdump.

That ist not the same with em1 - the flag is "always-on".

Any clues how to disable promiscuous mode in a running configuration?

Regards
Andre

[jggimi]

I have an em(4) device and have the same flag in ifconfig(8) output, running -current.

Looking through the commit log for sys/dev/pci/if_em.c, it appears that naddy@ made some revisions to promiscuous management for the em() driver back in June 2009 which are still in place. I do not see a discussion of this in the tech@ mailing list archives at that time, so I do not know the reason for the revision.

You might send him an Email to ask, if this is of concern to you.