[ExchangeList] Re: Exchange Que
- From: "John T \(Lists\)" <johnlist@xxxxxxxxxxxxxxxxxxx>
- To: <exchangelist@xxxxxxxxxxxxx>
- Date: Mon, 15 May 2006 22:59:12 -0700
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
<http://www.dnsstuff.com/tools/whois.ch?ip=206.248.138.108&cache=off>
&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 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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