Date: Tue, 8 May 2001 10:00:59 -0400 (EDT) From: Rob Harris <rharris@cidera.com> To: questions@freebsd.org Cc: hackers@freebsd.org Subject: natd forwarding broadcast broken?? Message-ID: <Pine.NEB.4.21.0105080949440.20577-100000@zorak.cidera.com>
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I've been ripping out what little hair I have left for two days on
this problem... Here's my situation:
I have a box (FreeBSD 4.0/i386) that has a ton of broadcast traffic coming
into it's fxp1 port. I want that traffic to show up on another LAN as
broadcast, effectively changing the dest addr of the packet from
255.255.255.255 to 172.31.85.255.
When I use ipfw and natd to change the dest ip of packets from
255.255.255.255 to a unicast address on that subnet,
(e.g. 172.31.85.10) it works just fine (i.e. I can see the traffic show up
on the 172.31.85/24 lan) However, when I set the dest IP for broadcast no
traffic shows up at all...
More specifically, in the above unicast case, I can see the traffic
leaving the destination box's ethernet interface (via netstat 1). In the
broadcast case, I see nothing leaving the ethernet interface.
Is this a limitation or a bug? Could it be a routing issue (though, not
sure how.)
When running in debug mode, natd is reportedly aliasing the packet
properly:
In [UDP] [UDP] 212.34.164.122:4054 -> 255.255.255.255:9090 aliased to
[UDP] 212.34.164.122:4054 -> 172.31.85.255:9090
Part of me thinks that for some reason IP NAT is not turning on the
broadcast flag for the socket, but I'm not sure.
Little help? Muchas Gracias.
--Rob
____________________________________________________________________________
Rob Harris 8037 Laurel Lakes Court, Laurel MD 301.598.0500 x2236
Cidera, Inc. rharris@cidera.com fax: 301.598.0837
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
"Don't rush me sonny. You rush a miracle man, you get rotten miracles."
--Miracle Max, The Princess Bride
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