Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 12 Oct 2015 14:28:58 +0000
From:      David DeSimone <ddesimone@verio.net>
To:        =?iso-8859-2?Q?Mi=B3osz_Kaniewski?= <milosz.kaniewski@gmail.com>
Cc:        "freebsd-pf@freebsd.org" <freebsd-pf@freebsd.org>
Subject:   RE: Creating span interface using 'dup-to' option
Message-ID:  <SN1PR08MB18210835207E194932EBB485BA310@SN1PR08MB1821.namprd08.prod.outlook.com>
In-Reply-To: <CAC4mxp5ar-Kvp5238VRfKEL6FiVOg7XXzmv8fE-zdEFYRk7cAw@mail.gmail.com>
References:  <CAC4mxp5ar-Kvp5238VRfKEL6FiVOg7XXzmv8fE-zdEFYRk7cAw@mail.gmail.com>

next in thread | previous in thread | raw e-mail | index | archive | help
The man page makes it clear that "dup-to" acts just like "route-to", except=
 that the original packet still routes the way it would have.  The implicat=
ion being that "dup-to" needs to determine where to route the new packet.

This means that the more useful form of this is likely to be:

    pass out on em0 dup-to ( em2 X.X.X.X ) no state

Where "X.X.X.X" is the IP of the host connected via em2 that will be receiv=
ing the duplicated packet.

The difference between using a bridge to accomplish this, vs. pf, is that p=
f operates at layer 3 and will not preserve the layer 2 mac headers, wherea=
s bridge will preserve these.

Hopefully this will fit your requirements.


-----Original Message-----
From: owner-freebsd-pf@freebsd.org [mailto:owner-freebsd-pf@freebsd.org] On=
 Behalf Of Milosz Kaniewski
Sent: Sunday, October 11, 2015 6:16 AM
To: freebsd-pf@freebsd.org
Subject: Creating span interface using 'dup-to' option

uname -a:
FreeBSD freebsd11_master.kvm 11.0-CURRENT FreeBSD 11.0-CURRENT #0 r285616:
Thu Jul 16 02:21:59 UTC 2015
root@releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC
 amd64


+----------+        +-----------+        +----------+
|          |     em0|           |em1     |          |
|  host1   +--------+  FreeBSD  +--------+  host2   |
|          |        |           |        |          |
+----------+        +-----------+        +----------+
                          |em2
                          |
                          |
                          v

Hi,

I have FreeBSD machine which forwards packets between host1 and host2. This
machine has also an additional interface (em2) which act as span interface
- all traffic between host1 and host2 is copied into it.
To achieve this scenario I can set bridge with em0 and em1 as members and
em2 as span interface. But I would like to get same result using pf
instead. So I tried to use this rules:

pass out on em0 dup-to em2 no state
pass out on em1 dup-to em2 no state

But it doesn't work. No packets appear on interface em2. I've checked same
configuration on OpenBSD and everything worked well.
Is there any difference in setting dup-to rule in FreeBSD and OpenBSD pf?

Thanks for help.

Best regards.
_______________________________________________
freebsd-pf@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-pf
To unsubscribe, send any mail to "freebsd-pf-unsubscribe@freebsd.org"

________________________________
This email message is intended for the use of the person to whom it has bee=
n sent, and may contain information that is confidential or legally protect=
ed. If you are not the intended recipient or have received this message in =
error, you are not authorized to copy, distribute, or otherwise use this me=
ssage or its attachments. Please notify the sender immediately by return e-=
mail and permanently delete this message and any attachments. makes no warr=
anty that this email is error or virus free. Thank you.
________________________________
This email message is intended for the use of the person to whom it has bee=
n sent, and may contain information that is confidential or legally protect=
ed. If you are not the intended recipient or have received this message in =
error, you are not authorized to copy, distribute, or otherwise use this me=
ssage or its attachments. Please notify the sender immediately by return e-=
mail and permanently delete this message and any attachments. NTT America m=
akes no warranty that this email is error or virus free. Thank you.
________________________________



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?SN1PR08MB18210835207E194932EBB485BA310>