Re: [Asrg] whitelisting server and not users

[Steven F Siirila <sfs@tc.umn.edu>]

On Wed, Apr 02, 2003 at 04:21:37PM -0500, Daniel Feenberg wrote:
> 
> On Wed, 2 Apr 2003, Steven F Siirila wrote:
> 
> > On Wed, Apr 02, 2003 at 04:06:32PM -0500, Kee Hinckley wrote:
> > > At 3:00 PM -0600 4/2/03, Steven F Siirila wrote:
> > Not a problem here since we also look up the EHLO name.  If that resolves
> > to the caller's IP address, it counts as good as a PTR record in our book.
> 
> But doesn't this open the door for the spammer to just get a throwaway
> domain name and authorize his own spam? The advantage of using the RDNS
> of the connecting host is that it is fixed by the ISP, who can
> be held responsible by RBLs. Since there are a finite number of IP address
> blocks, the ISP isn't going to want to repeatedly issue new IP addresses
> to the spammer. Without that enforcement tool, there isn't any real
> incentive in the system.

You are quite correct.  I realized this after I sent the mail.
It works well for open relays since the spammer cannot control the EHLO name.
However, open proxies and such are another story.

> 
> 
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Steven F. Siirila			Office: Lind Hall, Room 130B
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