An easy way to test if the smtp service is running on a domain or IP is to telnet to it. Below it shows an MX connect which is a DNS problem. If I telnet to "mail.dentrix.com 25" (this is telnetting to port 25 or the smtp service, I get a response as follows: 220 exchange.dentrix.com ESMTP Server (Microsoft Exchange Internet Mail Service 5.5.2650.21) ready This means the smtp or esmtp service is working properly. Now we need to test the IP address where the MX record DNS entry is point as shown below: MX connect fail "207.88.79.114" When I telnet to this entry "207.88.79.114 25" I get: 220 exchange.dentrix.com ESMTP Server (Microsoft Exchange Internet Mail Service 5.5.2650.21) ready As Len said the A record used as a fallback for dentrix.com is located at 207.88.79.116 and has a different e-mail server running as shown below: 220 dtxweb Microsoft ESMTP MAIL Service, Version: 5.0.2172.1 ready at Wed, 2 Ma y 2001 10:45:04 -0600 Now let's run a test on the first e-mail server that showed the MX record failure above. If we ping the first e-mail server "exchange.dentrix.com" we don't get an IP of 207.88.79.114 as shown in the MX connect fail message, but instead we get an IP of 172.21.1.5. I believe this is where the problem is, and it could be either a DNS issue or a routing issue in the dentrix.com side of the equation. ----- Original Message ----- From: "Len Conrad" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, May 02, 2001 2:44 AM Subject: Re: [IMail Forum] why is Imail dropping to another ip when first fails, MX vs A >When I look at dentrix.com; there is only one mx record; mail.dentrix.com > >The logs show: > >20010502 063644 127.0.0.1 SMTP (356) MX connect fail "207.88.79.114" >20010502 063644 127.0.0.1 SMTP (356) Connect dentrix.com >[207.88.79.116:25] (2) >20010502 063644 127.0.0.1 SMTP (356) 220 dtxweb Microsoft ESMTP MAIL >Service, Version: 5.0.2172.1 ready at Wed, 2 May 2001 07:47:21 -0600 >20010502 063644 127.0.0.1 SMTP (356) >EHLO stat.com >20010502 063644 127.0.0.1 SMTP (356) 250-dtxweb Hello [207.211.1.10] >20010502 063644 127.0.0.1 SMTP (356) 250-AUTH GSSAPI NTLM LOGIN >20010502 063644 127.0.0.1 SMTP (356) 250-AUTH=LOGIN >20010502 063644 127.0.0.1 SMTP (356) 250-TURN > > >An MX failure to 207.88.79.114 which is "mail.dentrix.com" > >But then it connects to the "A" record of 207.88.79.116 this is standard fallback behavior. >Maybe I misunderstood DNS records, but I thought if there were MX records >they were used for mail delivery and "A" records were ignored. The MX mail host doesn�t respond at all, so effectively there is no SMTP service there, so the SMTP client tries to deliver the domain�s A record. Len http://MenAndMice.com/DNS-training : SFO,CA; 7,8 May http://BIND8NT.MEIway.com : ISC BIND 8.2.3 "NT3" for NT4 & W2K http://IMGate.MEIway.com : Build free, hi-perf, anti-abuse mail gateways Please visit http://www.ipswitch.com/support/mailing-lists.html to be removed from this list. An Archive of this list is available at: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Please visit http://www.ipswitch.com/support/mailing-lists.html to be removed from this list. An Archive of this list is available at: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/
