Subject: [Asrg] Reverse DNS

From: [email-masked]
Date: Wed, 18 Jun 2003 12:56:04 -0500

> We are presently
requiring reverse DNS for IP addresses of MTA's which connect to our MX
(with exceptions, which are dwindling).  This has nothing to do with the
MAIL FROM domain, it simply means that if you connect to us, your IP address
must have a name, and that name must map back to your IP address.  What you
suggest above is exactly the sort of next step we're looking for; namely,
a DNS RR which tells the world that a particular host name has been designated
as an MTA (outgoing at least).  

There are a number of us advanced/small users with home offices who presently 
run our own outgoing SMTP mail server, behind a router using NAT.  Not all 
(valid, legitimate!) outgoing SMTP servers have fixed/permanent IP addresses.

Likewise, since I have a "residential" type high speed connection, I have *very* 
limited abilities (and that only because of my own domain names, but I don't 
have my own Net-accessible DNS server in any case) to manipulate the DNS records 
associated with those domains.

I suspect that a fair number of other consultant-type users are in a similar 
boat to myself on points like this.  It's the needs of some of us 
'advanced/small' users which the spf folks seem willing to totally ignore.

Gordon Peterson                  http://personal.terabites.com/
1977-2002  Twenty-fifth anniversary year of Local Area Networking!
Support the Anti-SPAM Amendment!  Join at http://www.cauce.org/
12/19/98: Partisan Republicans scornfully ignore the voters they "represent".
12/09/00: the date the Republican Party took down democracy in America.

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From: Steven F Siirila <[email-masked]>
Date: Wed, 18 Jun 2003 14:52:49 -0500

> (valid, legitimate!) outgoing SMTP servers have fixed/permanent IP addresses.

We do not allow connections from dynamic IP addresses.  There is simply no
way to account for unauthenticated email (that is what we're talking about
here) without at least tying the messages to a fixed IP address.  Of course
our users can let specific addresses through such a block based on a request
by the remote user (via URL).

> associated with those domains.

If you want to be an MTA, we feel you should be registered as one in DNS.
You don't even need the registered name to be in your domain, it simply
needs to map to a name which then maps back to the original IP address.
Without this, bad users in a dynamic IP range cannot be blocked individually.

> 'advanced/small' users which the spf folks seem willing to totally ignore.

In today's spam-ful world, something has to give.  Sites need an incentive to
tighten up controls and this is simply one more "tool" that can be used.

Even AOL has become more restrictive:

# telnet mailin-01.mx.aol.com 25
Trying 64.12.137.89...
Connected to mailin-01.mx.aol.com.
Escape character is '^]'.
220-rly-xg02.mx.aol.com ESMTP mail_relay_in-xg2.7; Wed, 18 Jun 2003 15:52:07 -0400
220-America Online (AOL) and its affiliated companies do not
220-     authorize the use of its proprietary computers and computer
220-     networks to accept, transmit, or distribute unsolicited bulk
220-     e-mail sent from the internet.  Effective immediately:  AOL 
220-     may no longer accept connections from IP addresses which 
220      have no reverse-DNS (PTR record) assigned.

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From: Benjamin Geer <[email-masked]>
Date: Wed, 18 Jun 2003 22:31:31 +0100

> (valid, legitimate!) outgoing SMTP servers have fixed/permanent IP addresses.

If you have dynamic IP addresses, why run your own MTA?  It's no use
for incoming mail, and for outgoing mail you could use your ISP's MTA.

Ben

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From: Yakov Shafranovich <[email-masked]>
Date: Thu, 19 Jun 2003 14:19:31 -0400

>'advanced/small' users which the spf folks seem willing to totally ignore.

I have my own SMTP server as well since my ISP does not provide one. 
HOWEVER, all IP addresses assigned by my ISP have reverse DNS records. I 
believe this is not a problem AS LONG AS ISPs will provide those problems.

RMX/SPF and similar systems on the other hand will cause a problem. Someone 
earlier suggested that free DNS systems such as dyndns.org would provide 
RMX functionality for such cases.

Yakov

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From: Jim Bauer <[email-masked]>
Date: Thu, 19 Jun 2003 19:07:31 -0400 (EDT)

> for incoming mail, and for outgoing mail you could use your ISP's MTA.

I don't trust my service provider to properly handle
outgoing mail.  I see the countless problem with their
pop server and even basic Internet connectivity.  IMO
they have amply demonstrated that they are not compentent.
Alternatives?  What alternatives?  They are a monopoly.