Well, I have no influence on addressing here, so any comments are mine alone. A lot of addressing schemes were created in the day before there was a huge issue with hostile dynamic addresses and the need to be able to identify them. Addressing assignments, of course, were (and still are to a large part) driven by routing efficiency. - Mark -----Original Message----- From: Steven J. Sobol [mailto:sjsobol@JustThe.net] Sent: Friday, April 29, 2005 4:40 PM To: Miller, Mark Cc: nanog@merit.edu Subject: RE: Schneier: ISPs should bear security burden On Fri, 29 Apr 2005, Miller, Mark wrote:

Unfortunately, a lot of static "business" DSL IP space is still on those lists and legitimate mail servers can get blocked. I usually use the DUL as a "white list" to negate hits on the traditional dnsbls

since those are almost always stale.

<assertion type="applies to USA, don't know about other countries"> That's because the ILECs, especially, don't feel the need to separate IPs on which servers are allowed, and IPs on which they aren't. SBC is the worst in this regard. No separation, no custom reverse DNS for DSL customers, no way to be absolutely certain if sending mail from a specific IP is a violation of SBC's TOS. </assertion> I've noticed that you work for Qwest. If the people designing your network DO have enough clue to separate IPs, bravo... but my experience is that many ISPs, especially ILECs/RBOCs, don't. -- JustThe.net - Apple Valley, CA - http://JustThe.net/ - 888.480.4NET (4638) Steven J. Sobol, Geek In Charge / sjsobol@JustThe.net / PGP: 0xE3AE35ED "The wisdom of a fool won't set you free" --New Order, "Bizarre Love Triangle"