[Dshield] RE: SMTP DNS record question

Richard Roy RoyR at justicetrax.com
Mon Jan 12 20:01:13 GMT 2004

Not sure, I had not thought of that, but will look into it rather
quickly here.
I tried to telnet to 25 on their MX set to 0 pref and could not, but
could to the other records all marked 10 so that could be the problem as

-----Original Message-----
From: list-bounces at dshield.org [mailto:list-bounces at dshield.org] On
Behalf Of YevetteM
Sent: Monday, January 12, 2004 12:24 PM
To: list at dshield.org
Subject: [Dshield] RE: SMTP DNS record question


I used the DNSStuff website to look up your mail server. (I hope this is
the one you are trying to send from in your email). Could it be that the
problem is not with them at all but with your side? (Specifically the
missing PTR
record?) Check out that DNSStuff returned:

Reverse DNS entries for MX records	 ERROR: One or more of your mail
server(s) have no reverse DNS (PTR) entries (if you see "Timeout" below,
it may mean that your DNS servers did not respond fast enough). RFC1912
2.1 says you should have a reverse DNS for all your mail servers. It is
strongly urged that you have them, as many mailservers will not accept
mail from mailservers with no reverse DNS entry. You can double-check
using the 'Reverse DNS Lookup' tool at the DNSstuff
<http://www.dnsstuff.com/>  site. The problem MX records are: [No reverse DNS entry (rcode: 3 ancount: 0)]
Mail	 FAIL	 Connect to mail servers	 ERROR: I could not
to one or more of your mailservers:
ERROR: corpmail.justicetrax.com Greeting indicates server is down: 421
SMTP service not available, closing transmission channel .
corpmail.justicetrax.com: Connection closed before I received all my
data (state 2). Your mailserver disconnected before it was done! This
may be the
result of a non-RFC-compliant mailserver or anti-spam program.	

Hope that helps -


<original message>
I am working to debug why I am having difficulties sending to a customer
email.  I have implemented a new firewall, and spam blocker, and have
yet to be able to point to either as the root of the problem.  So for
grins, I went to www.dnsstuff.com and did a querry on them.  They have 3
MX records, MX0, MX1, MX2 all with different hosts and IP addresses. The
weird thing is that all 3 have the same preference 10.  Is that possibly
the root of the problem.  I get a lot of mail to that domain marked
undeliverable and that the message has exceeded the time limit
specified.  If that is the problem, does anyone know of a reliable
source I can quote to explain what needs to be fixed without looking
like I don't know what I am talking about? </original message>

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