Re: Help Broadcasting a UDP packet on the LAN:URGENT

From: Wes Peters (wes_at_softweyr.com)
Date: 10/23/03

  • Next message: Kris Kennaway: "exclusive sleep mutex ifnet r = 0 (0xc07cc940) locked @ net/if.c:459"
    To: Charles Swiger <cswiger@mac.com>, net@freebsd.org
    Date: Thu, 23 Oct 2003 11:45:04 -0700
    
    

    On Thursday 23 October 2003 11:23 am, Charles Swiger wrote:
    > On Thursday, October 23, 2003, at 11:52 AM, Barney Wolff wrote:
    > > On Thu, Oct 23, 2003 at 01:55:55AM -0700, Wes Peters wrote:
    >
    > [ ... ]
    >
    > > What are you going to do when IPv6 comes into more general use, since
    > > it has no broadcast address?
    >
    > Are you asking what a IPv4-to-IPv6 translator (like gif?) should do, or
    > are you worried about the case of a machine configured for IPv6 only
    > and not for IPv4? I expect that most people will be using IPv4 for
    > quite some time; we don't have to do something for the IPv6-only case
    > to still have this be useful.

    Porting broadcast applications to IPv6 requires re-thinking the problem,
    because IPv6 sheds some of the problems of IPv4 and introduces a few of
    it's own. Address assignment, for instance, is much less a problem in
    IPv6, but not having the addresses centrally managed (by either a program
    or a human) introduces it's own difficulties.

    > > The whole VLAN thing is nasty, but I'd say that the general issue is
    > > does the box itself have a virtual interface on the VLAN, or is it
    > > merely switching on it. If the former, you send packets and process
    > > received packets up the stack. If the latter, you just do what any
    > > switch/bridge would do, because "you" (ie, higher layers) are not
    > > really
    > > on that layer-3 network.
    >
    > The all-ones broadcast is supposed to go to all physically connected
    > network segments, regardless of whether a particular interface is
    > ifconfig'ured with an IP that is part of a particular layer-3 subnet.
    > You should be able to send the broadcast packet out from an interface
    > which is up but does not have an IPv4 address assigned, right?

    So long as it IS configured with the IPv4 protocol, I'd say yes. Ditto
    for VLANs.

    -- 
            Where am I, and what am I doing in this handbasket?
    Wes Peters                                               wes@softweyr.com
    _______________________________________________
    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: Kris Kennaway: "exclusive sleep mutex ifnet r = 0 (0xc07cc940) locked @ net/if.c:459"

    Relevant Pages

    • Re: Help! "Martian" (packet) invasion via FiOS cablemodem
      ... The wording in "TCP/IP Blueprints" suggests that broadcast packet ... interface internal to cable modem, it's a device talking _to_ it. ... from Verizon or the Internet). ... If the packets annoy you, use iptables to quietly drop (all from ...
      (comp.os.linux.networking)
    • Re: Different behavior of pinging INADDR_BROADCAST?
      ... packets to INADDR_BROADCAST". ... should receive some sort of fix in handling INADDR_BROADCAST. ... hard to spot the right interface to output the broadcast to: ... identifying the interface the broadcast will go to. ...
      (freebsd-net)
    • Re: IPv6 "Jubmo Payload" Broadcast sample for Visual Basic .Net?
      ... I got this from the IPv6 Group: ... I have hit a 64K limit in UDP broadcasting. ... > of coding headache if I can get a IPv6 Broadcast to work with Jumbo ... The "jumbo payload" option is designed for very high speed networks that ...
      (microsoft.public.dotnet.languages.vb)
    • IPv6 "Jubmo Payload" Broadcast sample for Visual Basic .Net?
      ... IPv6 spec: ... IPv6 Sample C# Client/Server ... I am developing an application where I need to broadcast information to ... "Jumbo Payload", it could save me a good deal ...
      (microsoft.public.dotnet.languages.vb)
    • Re: NTP Limited Broadcast
      ... NTP does not ... broadcast on interfaces not associated with a broadcast command in ntp.conf. ... So in order to broadcast on 255.255.255.255 at least one network interface ... Chernobyl packets and the result as broadcast storms. ...
      (comp.protocols.time.ntp)