[ExchangeList] Re: Exchange Que

  • From: "Andrew English" <andrew@xxxxxxxxxxxxxxxxxxxxxx>
  • To: <exchangelist@xxxxxxxxxxxxx>
  • Date: Tue, 16 May 2006 14:35:05 -0400

Thanks for the lesson John. :)
 
I called the ISP this morning and requested they add the PTR to my IP. Now I 
have to wait 24 to 48 hours to see if they did set it up and if it's correct. 
 
Regards,
Andrew

________________________________

From: exchangelist-bounce@xxxxxxxxxxxxx on behalf of John T (Lists)
Sent: Tue 16/05/2006 1:59 AM
To: exchangelist@xxxxxxxxxxxxx
Subject: [ExchangeList] Re: Exchange Que



Just goes to show you Andrew how much you do not know by try to act like you do.

 

Class is now in session:

 

http://www.dnsreport.com/tools/dnsreport.ch?domain=Smoothrunnings.ca

This shows that there is one MX record for SmoothRunnings.ca which is 
mail.smoothrunnings.ca. The DNS servers for SmoothRunnings.ca have an A record 
for mail.smoothrunnings.ca which resolves to IP address 206.248.138.108. 

 

Everyone following along so far? Great! 

 

Now, e-mail servers on the Internet must have what is known as a PTR record, or 
reverse lookup record, for their IP address. Since the MX record for 
SmoothRunnings.ca resolves to IP address 206.248.138.10, that IP address must 
have a PTR record per RFCs. According to 
http://www.dnsstuff.com/tools/ptr.ch?ip=206.248.138.108+ it does indeed have a 
PTR record which is 206-248-138-108.dsl.teksavvy.com. Now, let's take a minute 
and look at that PTR record. The section furthest away from the root (Do we 
need a lesson on reading the Internet naming scheme?) is 206-248-138-108 which 
is a generic record indicating the IP. The next section is dsl which is a 
generic description indicating the type of service. The next section is 
teksavvy which is giving us an indication of who owns this IP address. If we 
then do a IPWHOIS on that IP address, 
http://www.dnsstuff.com/tools/whois.ch?ip=206.248.138.108&cache=off, we then 
for sure know that the IP address 208.248.138.108 is owned by TekSavvy 
Solutions of Ontario Canada. 

 

Everyone still with me? Great!

 

Now, a little side lesson here. The MX record for SmoothRunnings.ca is 
mail.smoothrunnings.ca which resolves to IP address 206.248.138.108 which has a 
PTR record. However, the PTR record it has is not appropriate in terms of 
e-mail anti-spam software. So, while it does technically pass a PTR test, it 
fails a PTR to MX record match which it would then be docked a point or 2.

 

Now domain 2.

 

http://www.dnsreport.com/tools/dnsreport.ch?domain=autosoldnow.com shows that 
there is one MX record for the domain, mail.autosoldnow.com. That MX record has 
a matching A record on NetworkNonSolutions that resolves to IP address 
67.69.15.19. (Yes, I spelled the name of the domain registrant used correctly.)

 

Since we already learned that e-mail servers must have a PTR record, we will 
check at http://www.dnsstuff.com/tools/ptr.ch?ip=67.69.15.19 we find that there 
is no PTR record for this IP address. If we fully read the page, we will see 
that we need to contact someone who is in charge of NS2.BellGlobal.com to have 
them create the PTR record, or have them delegate authority for the IP to us. 
If we go to http://www.dnsstuff.com/tools/whois.ch?ip=67.69.15.19 we see that 
the 67.68.0.0 block is "owned" by Bell Canada and further that Bell Canada has 
assigned the 67.69.15.0 block to AutoSoldNow, Inc. So, either some one needs to 
contact Bell Canada to create the PTR record for IP address 67.69.15.19 and 
pointing to mail.autosoldnow.com OR have Bell Canada delegate control of the IP 
block 67.69.15.0 to your DNS server in which case you would have to create a 
PTR zone of 15.69.67.in-addr.arpa and then add a record for 
mail.autosoldnow.com.

 

So, let's review. An e-mail server requires an MX record, an A record and a PTR 
record. The PTR record is the responsibility of the IP owner or its delegate.

 

Class dismissed.

 

John T

eServices For You

 

"Seek, and ye shall find!"

 

-----Original Message-----
From: exchangelist-bounce@xxxxxxxxxxxxx 
[mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Andrew English
Sent: Monday, May 15, 2006 7:31 PM
To: exchangelist@xxxxxxxxxxxxx
Subject: [ExchangeList] Re: Exchange Que

 

John, 

 

I wouldn't go as far as saying no Domain registrar supports PTR records. Let me 
show you:

 

autosoldnow.com on Network Solutions:

 

(FAIL) Reverse DNS entries for MX records

 

ERROR: The IP of 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 <http://www.DNSstuff.com/pages/rfc1912.htm>  2.1 
says you should have a reverse DNS for all your mail servers. It is strongly 
urged that you have them, as many mail servers will not accept mail from mail 
servers with no reverse DNS entry. You can double-check using the 'Reverse DNS 
Lookup' tool at the DNSstuff <http://www.DNSstuff.com>  site (it contacts your 
servers in real time; the reverse DNS lookups in the DNS report use our local 
caching DNS server). The problem MX records are:  19.15.69.67.in-addr.arpa [No 
reverse DNS entry (rcode: 3 ancount: 0) (check it 
<http://www.dnsstuff.com/tools/ptr.ch?ip=67.69.15.19> )]

 

 

Smoothrunnings.ca on Register.com:

 

(PASS) Reverse DNS entries for MX records

 

OK. The IPs of all of your mail server(s) have reverse DNS (PTR) entries. 
RFC1912 <http://www.DNSstuff.com/pages/rfc1912.htm>  2.1 says you should have a 
reverse DNS for all your mail servers. It is strongly urged that you have them, 
as many mail servers will not accept mail from mail servers with no reverse DNS 
entry. Note that this information is cached, so if you changed it recently, it 
will not be reflected here (see the www.DNSstuff.com Reverse DNS Tool 
<http://www.dnsstuff.com>  for the current data). The reverse DNS entries are: 
108.138.248.206.in-addr.arpa 206-248-138-108.dsl.teksavvy.com. [TTL=3600]

 

Regards,

Andrew

 

 

________________________________

From: exchangelist-bounce@xxxxxxxxxxxxx 
[mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of John T (Lists)
Sent: Monday, May 15, 2006 5:53 PM
To: exchangelist@xxxxxxxxxxxxx
Subject: [ExchangeList] Re: Exchange Que

 

Once again Andrew, you are incorrect. No Domain name registrar supports PTR 
records for a very valid reason; PTR records can only be created by the entity 
that controls the IP address, of which no Domain registrar does.

 

John T

eServices For You

 

"Seek, and ye shall find!"

 

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