nanog mailing list archives
Re: SMURF amplifier block list
From: kline () uiuc edu (Charley Kline)
Date: Tue, 14 Apr 1998 13:42:40 -0400
In message <19980414111503.06128 () mcs net>, you wrote:
Not often. Few people are actually supernetting within a given broadcast domain. There's still an awful lot of hardware that doesn't work right in that environment.
But subnets of class B's may be larger than /24 and have host numbers of .255 and .0 in them. That's true all over this campus. It may be reasonable to filter x.x.x.255 addresses from class C's or /24 blocks, but you cannot filter all addresses that end in .255 without filtering out a number of completely legitimate hosts.
The larger problem is that subnetted /24s still are wide open. This kind of filter won't block anything from their broadcast addresses, since they're not the .255 address.
Indeed yes! There are also many subnets smaller than /24 where the broadcast address does not end in .255 that would still be open for smurfing even in the presence of this .255 filter. The x.x.x.255 filter is an extremely bad idea. /cvk
Current thread:
- Re: SMURF amplifier block list, (continued)
- Re: SMURF amplifier block list Jason L. Weisberger (Apr 13)
- Re: SMURF amplifier block list Dean Anderson (Apr 13)
- Re: SMURF amplifier block list Forrest W. Christian (Apr 13)
- Re: SMURF amplifier block list Alex P. Rudnev (Apr 14)
- Re: SMURF amplifier block list Forrest W. Christian (Apr 14)
- Re: SMURF amplifier block list Michael Shields (Apr 14)
- Re: SMURF amplifier block list Brett Frankenberger (Apr 14)
- Re: SMURF amplifier block list Stephen Sprunk (Apr 13)
- Re: SMURF amplifier block list Aaron Beck (Apr 14)
- Re: SMURF amplifier block list Karl Denninger (Apr 14)
- Re: SMURF amplifier block list Charley Kline (Apr 14)
- Re: SMURF amplifier block list Stephen Sprunk (Apr 14)
- Re: SMURF amplifier block list Stephen Sprunk (Apr 14)
- Re: SMURF amplifier block list Karl Denninger (Apr 14)
- Re: SMURF amplifier block list Aaron Beck (Apr 14)
- Re: SMURF amplifier block list Stephen Sprunk (Apr 14)
- Re: SMURF amplifier block list - READ THIS Karl Denninger (Apr 14)
- Message not available
- Re: SMURF amplifier block list - READ THIS Jay R. Ashworth (Apr 14)
- Re: SMURF amplifier block list - READ THIS Mark Milhollan (Apr 14)
- Re: SMURF amplifier block list - READ THIS Michael Dillon (Apr 14)
- Re: SMURF amplifier block list - READ THIS Dax Kelson (Apr 15)