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 220.127.116.11. 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 18.104.22.168, that IP address must have a PTR record per RFCs. According to http://www.dnsstuff.com/tools/ptr.ch?ip=22.214.171.124+ 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=126.96.36.199 <http://www.dnsstuff.com/tools/whois.ch?ip=188.8.131.52&cache=off> &cache=off, we then for sure know that the IP address 184.108.40.206 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 220.127.116.11 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 18.104.22.168. (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=22.214.171.124 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=126.96.36.199 we see that the 188.8.131.52 block is "owned" by Bell Canada and further that Bell Canada has assigned the 184.108.40.206 block to AutoSoldNow, Inc. So, either some one needs to contact Bell Canada to create the PTR record for IP address 220.127.116.11 and pointing to mail.autosoldnow.com OR have Bell Canada delegate control of the IP block 18.104.22.168 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: 22.214.171.124.in-addr.arpa [No reverse DNS entry (rcode: 3 ancount: 0) (check it <http://www.dnsstuff.com/tools/ptr.ch?ip=126.96.36.199> )] 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: 188.8.131.52.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!"