Re: broadcast udp packets ...

From: Julian Elischer (julian_at_elischer.org)
Date: 07/02/03

  • Next message: Matthew Grooms: "Re: broadcast udp packets ..." 
    Date: Tue, 1 Jul 2003 15:12:43 -0700 (PDT)
To: Matthew Grooms <mgrooms@shrew.net>

    you can use netgraph to make a "virtual bridge"

    see /usr/share/examples/netgraph for an example of a single bridge.

    attach one of the bridge hooks on each site to an ng_socket node that
    has made a udp vpn..
    see the vpn example for that..

    by combining both the bridge and vpn examples you can hook the two
    sites together in a bridged manner.

    On Tue, 1 Jul 2003, Matthew Grooms wrote:

    > Well,
    >
    > Ok, sounds stupid right, well here is a bit of background. My friend and
    > I have an IPSEC tunnel in between our two private networks connected by BSD
    > firewalls w/ cable modems. Without going into too much detail, certain
    > programs ( win32 games ) use all-routes broadcasts to advertise the info
    > pertaining to the workstaion hosting a particular game. After much searching,
    > I could find no mechanism in FreeBSD that would allow me to pass these
    > broadcasts from a private network, across the IPSEC tunnel and to the distant
    > private network. ( tried all sorts of nat and bridging configurations )
    >
    > As a result, I decided to write a small relay daemon that used bpf to
    > pick up the broadcast messages from the local private network, forward them
    > to a peer that in turn drops it on to the distant private network. ( I know,
    > its a lot of work to play a game but it sounded like a fun project ) In any
    > case, I have most of it working well but am getting loops when the bpf dropps
    > the packet on the wire at the far end. It reads the packet in after writing
    > it out and forwards it back to the originating relay partner, just like a
    > really bad pong game. Setting BIOCSSEESENT on the fd does not seem to do the
    > trick. Any Ideas?
    >
    > In any case, I wrote a quick little program to generate a broadcast
    > message for use with testing the relay daemon ( I got tired of waiting for
    > bootp requests to be picked up by my cable modem as a test case ).
    > Unfortunately, I can never get the test program generate an all-routes
    > broadcast, they always come out as network directed broadcasts.
    >
    > <Sigh> ... If there is not a more conventional way of going about it, I guess
    > I will just have to generate one using the bpf.
    >
    > On 7/1/2003, "Chuck Swiger" <cswiger@mac.com> wrote:
    >
    > >Matthew Grooms wrote:
    > >> Is there any way to generate a udp broadcast ( all routes
    > >> 255.255.255.255 ) packet using a standard sendto() without it being
    > >> translated into a local network broadcast? Is this just not "allowed"?
    > >
    > >Are you trying to use 255.255.255.255 to reach something not on a local
    > subnet?
    > >
    > >If you have multiple interfaces, a broadcast to 255.255.255.255 should go
    > out on
    > >all of them. That being said, the all-ones broadcast address means "all
    > local
    > >networks", and most routers will block such traffic from passing on in any
    > event.
    > >
    > >--
    > >-Chuck
    > >
    > _______________________________________________
    > freebsd-net@freebsd.org mailing list
    > http://lists.freebsd.org/mailman/listinfo/freebsd-net
    > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
    >

    _______________________________________________
    freebsd-net@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-net
    To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"

  • Next message: Matthew Grooms: "Re: broadcast udp packets ..."

    Relevant Pages

    • Re: broadcast udp packets ...
      ... it could be useful to have flexable utility that could be used to bridge ... distant broadcast domains. ... >> pick up the broadcast messages from the local private network, ...
      (freebsd-net)
    • Re: Is it possible to bridge three NIC on a Windows 2000 Server
      ... A bridge propagates broadcasts; a router does not. ... you have one new Broadcast domain since a bridge ... > would end up with two physical segments that make up a single broadcast ...
      (microsoft.public.win2000.networking)
    • Re: DHCP over a dd-wrt client bridge.
      ... broadcast packets). ... So it's not a true transparent bridge. ... the wireless MAC the backhaul. ... which also uses an all 1's broadcast packet. ...
      (alt.internet.wireless)
    • Re: DHCP over a dd-wrt client bridge.
      ... broadcast packets). ... So it's not a true transparent bridge. ... the wireless MAC the backhaul. ... which also uses an all 1's broadcast packet. ...
      (alt.internet.wireless)
    • Re: Is it possible to bridge three NIC on a Windows 2000 Server
      ... They could be referring specifically to a bridge type switch ... One uses Router methods (routing tables ... So if you join to broadcast domains with a Bridge, ...
      (microsoft.public.win2000.networking)