RE: what's the meaning 255.255.255.255?

["David Gillett" <gillettdavid () fhda edu>]

  211.1.1.255 is the broadcast address for 211.1.1.0/24.\

  255.255.255.255 is the broadcast address for a device that
doesn't know (or perhaps just doesn't care) what network it's
on.  The local TCP/IP stack will convert it to a layer 2
(usually Ethernet) broadcast, so it will go to everyone on the
local segment.

  Since routers don't forward broadcasts(*), this will not pass
the router.

David Gillett

(*) 255.255.255.255 will often appear as the destination for
DHCP requests -- the sending device doesn't have any way to know
what the "normal" local broadcast address is until it gets that
information from DHCP.
  Note also that DHCP is one of several such services which *may*
be translated from a local broadcast to a routed unicast if a
"helper" address or service proxy is defined.  In this case, the
traffic goes beyond the local router, but is no longer a broadcast
when it does so.


> -----Original Message-----
> From: SB CH [mailto:chulmin2 () hotmail com]
> Sent: March 2, 2003 17:33
> To: security-basics () securityfocus com
> Subject: what's the meaning 255.255.255.255?
>
>
> Hello, all
>
> I have operated 2 /24 network(like 211.1.1.0/24, 211.1.2.0/24
> ) at one
> router.
> I can see 255.255.255.255 traffic.
>
> Then what's the defference between 255.255.255.255 and 211.1.1.255 ?
> 255.255.255.255 traffic spreads all over the network?
> 255.255.255.255 pass the router if there isn't any access-list?
> 211.1.2.0/24 range can recognize 255.255.255.255 traffic too?
>
> Thanks in advance,
>
>
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