Subject: More frustrating that not having [ietf] (Fw: Undelivered Mail Returned to Sender)

From: Mark Smith <[email-masked]>
Date: Thu, 18 Dec 2003 01:30:19 +1030

I find this more frustrating. I have a dynamic IP address, because fixed IP address ADSL isn't very common here in Australia. So I use DYNDNS to map my domain MX records. I can't get matching PTR records.

I'm assuming my mail bounced because I don't have matching PTR and MX records.

Why should email assume fixed IP addresses for email delivery, or rather, matching PTR and MX records ?

Begin forwarded message:

Date: Thu, 18 Dec 2003 01:11:28 +1030 (CST)
From: [email-masked] (Mail Delivery System)
To: [email-masked]
Subject: Undelivered Mail Returned to Sender

This is the Postfix program at host nosense.org.

I'm sorry to have to inform you that the message returned
below could not be delivered to one or more destinations.

For further assistance, please send mail to <postmaster>

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			The Postfix program

<[email-masked]>: host mail.netaxs.com[207.8.186.26] said: 550 5.7.1
    <[email-masked]>... 203.102.233.19 is unwelcome here

UmVwb3J0aW5nLU1UQTogZG5zOyBub3NlbnNlLm9yZwpBcnJpdmFsLURhdGU6IFRodSwgMTggRGVj
IDIwMDMgMDE6MTA6NTQgKzEwMzAgKENTVCkKCkZpbmFsLVJlY2lwaWVudDogcmZjODIyOyBjb29r
QGNvb2tyZXBvcnQuY29tCkFjdGlvbjogZmFpbGVkClN0YXR1czogNS4wLjAKRGlhZ25vc3RpYy1D
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NTUwIDUuNy4xCiAgICA8Y29va0Bjb29rcmVwb3J0LmNvbT4uLi4gMjAzLjEwMi4yMzMuMTkgaXMg
dW53ZWxjb21lIGhlcmUKCg==

Subject: Re: Adding SpamAssassin Headers to IETF mail
From: Mark Smith <[email-masked]>
To: Gordon Cook <[email-masked]>
Cc: [email-masked]
Date: Thu, 18 Dec 2003 01:10:53 +1030

I just match on either the 

"Sender: [email-masked]"

header, or the ML specific email address I've created.

I'm using Sylpheed though, it seems to be more flexible on matching header fields than most other email clients I've used in the past.

On Wed, 17 Dec 2003 09:13:13 -0500
Gordon Cook <[email-masked]> wrote:

> >On Wed, Dec 17, 2003 at 08:00:38AM +0200, Pekka Savola wrote:
> >>
> >>  I don't-  IMHO it's stupid to waste the precious bits in the subject
> >>  line to say "[ietf] " because there is no need for such.  The messages
> >>  can be filtered better using other thods as well, and humans can look
> >>  at the headers..
> >
> >I agree, for filtering everything's in the header already.
> >
> >Tim
> 
> I  do not use eudora to forward list mail to separate mail boxes. 
> therefore if i don't start list filtering into seperate mail boxes, i 
> am forced to guess where a piece of mail might be ietf since adding 6 
> characters to ever subject headers is judged unhelpful and 
> unacceptable?
> 
> There is no sure way at all to tell from a subject line whether its 
> IETF and to complain about adding 6 ascii characters to a subject 
> line wasting bits if it gives several thousand humans a hint as to 
> whether to open and read, or delete unopened, or delete mail to spam 
> mail box seems to be strange.  But this point of view i guess is why 
> the list keepers have not yet and probably never will do what most of 
> the other lists that I receive do.
> 
> -- 
> =============================================================
> The COOK Report on Internet Protocol,  609 882-2572 (PSTN) 703 738-6031
> (Vonage) Subscription info & prices at 
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> years of back issues at http://www.cafeshops.com/cookreportinter.6936314 
> E-mail [email-masked] or use [email-masked] Free World Dial up 17318
> =============================================================
>

---

From: Gordon Cook <[email-masked]>
Date: Wed, 17 Dec 2003 10:16:00 -0500

I share your frustration.   Yes this is another casualty of the spam 
wars.  This is my isp...not me.  Bankrupt in june these folk added 
every ip block that they could find on every spam black hole list to 
their null routing tables and in short order place in japan, nepal, 
new zealand and mexico could no longer reach me.  I have an alternate 
email that dot forwards on my home pages and by january 1 i hope to 
have moved completely...web and email service, to a different ISP.

>I find this more frustrating. I have a dynamic IP address, because 
>fixed IP address ADSL isn't very common here in Australia. So I use 
>DYNDNS to map my domain MX records. I can't get matching PTR records.
>
>Reporting-MTA: dns; nosense.org
>Arrival-Date: Thu, 18 Dec 2003 01:10:54 +1030 (CST)
>
>Final-Recipient: rfc822; [email-masked]
>Action: failed
>Status: 5.0.0
>Diagnostic-Code: X-Postfix; host mail.netaxs.com[207.8.186.26] said: 550 5.7.1
>Received: from Dupy2.nosense.org (19.cust6.nsw.dsl.ozemail.com.au 
>[203.102.233.19])
>	by nosense.org (Postfix) with SMTP
>	id 262643F02A; Thu, 18 Dec 2003 01:10:54 +1030 (CST)
>Message-Id: 
><[email-masked]>
>In-Reply-To: <p06010201bc061162f9f4@[10.0.1.3]>
>References: <[email-masked]>
>	<[email-masked]>
>	<[email-masked]>
>	<p06010201bc061162f9f4@[10.0.1.3]>
>Organization: The No Sense Organisation
>X-Mailer: Sylpheed version 0.9.6 (GTK+ 1.2.10; i686-pc-linux-gnu)
>Mime-Version: 1.0
>Content-Type: text/plain; charset=US-ASCII; x-Spamnix=checked
>Content-Transfer-Encoding: 7bit
>
>I'm using Sylpheed though, it seems to be more flexible on matching 
>header fields than most other email clients I've used in the past.
>

---

From: John Stracke <[email-masked]>
Date: Wed, 17 Dec 2003 10:15:34 -0500

>Why should email assume fixed IP addresses for email delivery, or rather, matching PTR and MX records ?
Because spammers target home users with broadband connections, and try 
to crack their systems to use them as open relays.  As a result, some 
ISPs have taken this step; they figure you can always send mail via your 
ISP's SMTP server.  Yes, it's dain-bramaged.

-- 
/================================================================\
|John Stracke      [email-masked]                         |
|Principal Engineer|http://www.centive.com                       |
|Centive           |My opinions are my own.                      |
|================================================================|
|Never underestimate the power of human stupidity. --I forget who|
\================================================================/

---

From: Keith Moore <[email-masked]>
Date: Wed, 17 Dec 2003 11:28:36 -0500

> have moved completely...web and email service, to a different ISP.

Maybe there needs to be a "stupid ISP tricks" RFC.  I'm perfectly serious.

---

From: Ari Ollikainen <[email-masked]>
Date: Wed, 17 Dec 2003 08:36:15 -0800

At 10:16 AM -0500 12/17/03, Gordon Cook wrote:
>I share your frustration.   Yes this is another casualty of the spam wars.  This is my isp...not me.  Bankrupt in june these folk added every ip block that they could find on every spam black hole list to their null routing tables and in short order place in japan, nepal, new zealand and mexico could no longer reach me.  I have an alternate email that dot forwards on my home pages and by january 1 i hope to have moved completely...web and email service, to a different ISP.

	While you're at it, get a mail client that can filter incoming
	email and learn how to set up the filters...so that this silly
	thread can die.

 _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
 You can't depend on your judgement when your imagination is out of focus.	
						          -- Mark Twain.
 _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/

---

From: shogunx <[email-masked]>
Date: Wed, 17 Dec 2003 22:14:43 -0500 (EST)

> Why should email assume fixed IP addresses for email delivery, or rather, matching PTR and MX records ?

You could have the first authoritative nameserver listed with your
registrar as the dyndns address, then do your dns locally for your domain.
Two scripts on http://sleekfreak.ath.cx:81/technology.html allow this,
regenerating the zone file every time the address changes.  The two
scripts run under client/server model presently.  They would have to be
merged or called sucessively to make it work on one host.

Scott

>     <[email-masked]>... 203.102.233.19 is unwelcome here

sleekfreak pirate broadcast
world tour 2002-3
live from the pirate hideout
http://sleekfreak.ath.cx:81/

---

From: "Theodore Ts'o" <[email-masked]>
Date: Wed, 17 Dec 2003 16:43:26 -0500

> merged or called sucessively to make it work on one host.

The problem is how do you update the PTR record?  It's owned by the
ISP, not by you.  My solution to the problem is to rent a 1U space at
a colo facility (via a co-op arrangement with a dozen or so
like-minded folks in Boston) which runs my DNS and my mail server, and
since it is at a fixed IP address, it avoids this kind of brain
damage.  It costs me $50/month for the 1U rackspace plus fixed IP
address at colo facility, but if you have dynamic IP address via DSL,
you really are a second class citizen on the Internet, and there isn't
much that can be done about it.

					- Ted

---

From: shogunx <[email-masked]>
Date: Thu, 18 Dec 2003 00:05:23 -0500 (EST)

On Wed, 17 Dec 2003, Theodore Ts'o wrote:

> ISP, not by you.

You the problems with forward or reverse dns?

> My solution to the problem is to rent a 1U space at

Actually my family has a large Tier 1 NOC one hop from the backbone in two
directions in Atlanta.  Its free for me.  I chose to solve the problem
locally because your latter statement has some truth to it.  Mail to many
ISP's is filtered from "home" IP addresses, forcing the use of offshore
mailservers to reach these these ISP's users.  Rediculous.  Hence, I voice
my disapproval in the form of code.

Scott

---

From: Dean Anderson <[email-masked]>
Date: Wed, 17 Dec 2003 17:37:34 -0500 (EST)

> > > rather, matching PTR and MX records ?

They shouldn't assume this.  PTR records are optional.  Some places in the
world don't have them at all. Some ISPs don't have them because they
choose not to bother.  Some that choose to bother, don't have them "right" 
per the demands of the reverse DNS checkers.

The claim that "if forward and reverse DNS match, then you can trust the
IP"  is false. No such trust relationship can be deduced from the relevant
RFCs, and the use of reverse DNS is optional.

The few people that promote such configurations are well aware that they
are violating RFCs, and they are aware that they are creating security
vulnerabilities by causing people to place inappropriate faith and trust
in DNS responses.

The "Reverse DNS check" also fails if there is not a one-host/one-IP
mapping. There is no support for this condition in the DNS RFCs so it too
is a false assumption. This condition is often violated by multihomed
hosts.

The usual reason given for this check is to block spam. But they should
also know that spammers neither choose their IP addresses, nor whether
those IP addresses have reverse DNS. Reverse checking as a spam indicator
is just checking the value of random variable that has no relationship to
spam.

It is an irony that the residential ISPs most plagued by spammers
generally have reverse DNS configured such that this test passes. If you
were to use DNS as a spam indicator, it would be more sensible to choose
the presence of Reverse as an indicator of spam, than an indicator of
non-spam.  But it would still be testing the particular value of a random 
variable.

		--Dean