ISPs blocking SMTP connections from dynamic IP address space

Doug Poland doug at
Thu Aug 7 07:01:54 PDT 2003

On Thu, Aug 07, 2003 at 03:27:15PM +0200, Roger 'Rocky' Vetterberg wrote:
> Doug Poland wrote:
> >Within the last two months both AOL and Time Warner Road Runner
> >have implemented port 25 blocks from hosts with IP addresses in the
> >"dynamic address space".  Time Warner claims other major ISPs
> >are/will be implementing the same policy.
> >
> >
> >A little help here?
> >
> >
> Sorry, but I cant help you here, I fully agree with AOL and the big
> guys.  We have to take some serious action against spam, 
I hate spam as much as the next guy.  But 

> piss a lot of people off, but as they say: you cant make an omelett
> without breaking some eggs.  I say block the dynamic address space,
This is where I disagree.  What is the "dynamic address space" anyway?
DSL, dial-up, and cable modem providers IP ranges?  This separates the
world into the "haves" and "havenots" based on static($$$) vs.
dynamic IP range.  So the big ISPs get to say,  
	"We will not accept a connection from a host, on port 25,
	unless the IP originates from an IP range we have decided is

What happens when the ISPs decide,

	"We will not accept a connection from a host unless the MTA is on
	the approved list, i.e., Microsoft Exchange"

> block everything that lacks proper reverse dns
I have proper reverse DNS.  I don't get to connect because of this
"dynamic IP range" issue.  If one has proper reverse dns, should one
be blocked because the host IP comes from a "dynamic address space"?


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