On Thu, Oct 07, 2004 at 07:51:07AM +0200, Frank Ellermann wrote:
|
| Sounds like MTAMARK going SPF (spf2.0/ptr). That's a rather
| expensive solution compared with DUL-lists. But maybe it
| could be combined, the MX continues to use the DUL list,
| the DUL list uses MTAMARK (resp. spf2.0/ptr) as one of its
| sources.
|
I think one possible optimization there is for ISPs to agree
on a convention for publishing DUL data in SPF format, which
RBLs can then suck down automatically.
For example, broadband.net could publish
_dul.broadband.net IN TXT "batch spf2.0/ptr -ip4:192.0.2.0/24
-ip4:192.0.3.0/24 ..."
And an RBL system would probe for _dul.*.{com,net} etc and
automatically build its DUL from the resulting entries. Of
course you have to be careful about cross-domain poisoning
(_dul.badguy.com could list -ip4:0.0.0.0/8) but sanity
checks shouldn't be hard.