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Dealing with MXlo stupidity - any ideas ?

I am looking for ideas on how to deal with the insanity that MXlo is causin=
g for me.

"MXlo means DNS resource records of the MX type that have a value of localh=
ost. The name comes from combining the MX from Mail eXchange and the lo abb=
reviation for a loopback networking interface, and is an anti-spam techniqu=
e that is growing in popularity with network administrators who manage a la=
rge number of unused legacy domain names."

We send mail on behalf of our customers (A) to their customers (B).

If (A) gets the email address for (B) wrong and the resultant email address=
 is for a domain that is parked with a parking site (e.g. Sedo Parking) tha=
t uses MXlo the DSN my sytem sends to (A) reports that my system is miconfi=
gured.

e.g.

554 5.0.0 MX list for abhotel.com. points back to myserver.com.au
554 5.3.5 Local configuration error

This makes me look bad to (A) as they think I have a setup problem which I =
do not.

This is caused by the MX record for the domain being as follows:

dig mx abhotel.com

;; QUESTION SECTION:
;abhotel.com.                   IN      MX

;; ANSWER SECTION:
abhotel.com.            3600    IN      MX      0 localhost.

;; AUTHORITY SECTION:
abhotel.com.            172800  IN      NS      ns1.sedoparking.com.
abhotel.com.            172800  IN      NS      ns2.sedoparking.com.

;; ADDITIONAL SECTION:
localhost.              10800   IN      A       127.0.0.1
localhost.              10800   IN      AAAA    ::1
ns1.SEDOPARKING.com.    97644   IN      A       209.200.164.69
ns2.SEDOPARKING.com.    97644   IN      A       209.200.165.74

;; Query time: 500 msec
;; SERVER: 192.168.1.253#53(192.168.1.253)
;; WHEN: Mon Sep 05 12:55:58 AEST 2016
;; MSG SIZE  rcvd: 209

Thanks for violating two RFCs for every domain parked by Sedo...

Can anyone suggest a way I can "fix" this  or am I doomed ?
0
mrludo001
9/5/2016 3:00:29 AM
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> abhotel.com.            3600    IN      MX      0 localhost.

> abhotel.com.            172800  IN      NS      ns1.sedoparking.com.
> abhotel.com.            172800  IN      NS      ns2.sedoparking.com.

> Can anyone suggest a way I can "fix" this  or am I doomed ?

Some suggestions:

Take a look at badmx and use it also for check_rcpt.

Write your own DNS map to look up NS, check whether it matches
sedoparking.com
and reject those addresses.


-- 
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is too lazy to trim his article, and it's wasting the time of all readers.
0
Claus
9/5/2016 1:26:17 PM
Thanks for the advice.
0
mrludo001
9/5/2016 10:18:12 PM
On Monday, September 5, 2016 at 5:00:32 AM UTC+2, mrlu...@gmail.com wrote:
> I am looking for ideas on how to deal with the insanity that MXlo is causing for me.

> ;; ANSWER SECTION:
> abhotel.com.            3600    IN      MX      0 localhost.

I'm using a custom milter to reject those recipients.

MIMEDefang is a generic milter you can code a custom handler with. For your situation, it seems exaggerated, though.
0
ska
9/6/2016 6:06:26 AM
Reply: