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Subject: Unable to send to specific domains

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C P

Canada
Member since
2/12/2007

Platinum Membership
Posts: 48

7/21/2008 05:30 PM
Hi Everyone. I am having trouble sending emails to 2 specific domains. I am getting a variety of errors. I am using pop3 connector to get email and the SBS server is 2003 R2 SP2 and currently patched up to date. First message is There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. tarpondscleanup.ca #5.5.0 smtp;557 Your IP does not have a reverse DNS entry. Disconnecting... I do have reverse DNS entry. The other error is You do not have permission to send to this recipient. For assistance, contact your system administrator. tarpondscleanup.ca #5.7.1 smtp;501 5.7.1 ... Sender IP must resolve> These other domains are getting emails fine fom other sources. i did some research but did not come up with much to resolve the issue

Steve Moss User is Offline

Telford, U.K.
Member since
8/30/2006

Registered Users
Posts: 104

7/21/2008 06:10 PM
While you say you have a PTR record, if it is of a generic type (some ISPs provide these automatically for IP addresses from a dynamic range) then some mail servers will reject it. If you tell us your (public) domain name for your server, we can check your public DNS records. Given that you have public DNS records, there's no real harm in quoting your domain name here - munge it if you prefer so it is decipherable by humans, as in mail [dot] domain [dot] com, or some such.

C P

Canada
Member since
2/12/2007

Platinum Membership
Posts: 48

7/22/2008 01:49 PM
No problem. Our domain name is tarpondscleanup.ca Like I mentioned we use pop3 to get our mail from our webhost. I have a virtual SMTP server set up locally on the SBS box. We have a static IP address from our local carrier. My long term plan is to switch to SMTP but I am a little nervous switching it from pop3. Let me know if you have any other questions or need details.

Steve Moss User is Offline

Telford, U.K.
Member since
8/30/2006

Registered Users
Posts: 104

7/22/2008 03:54 PM
The tarpondscleanup.ca domain is hosted at your isp (phpwebhosting.com), and there are DNS A records for mail.tarpondscleanup.ca and www.tarpondscleanup.ca, both of which point to your ISP's servers for mail and web hosting. There is also a reverse DNS (rDNS) record for mail.tarpondscleanup.ca which resolves to amber.phpwebhosting.com. So, your incoming mail is routed to your pop3 account with your ISP, and mail sent from your ISP account has proper rDNS. However, none of this pertains to your SBS (that you use for sending mail). You/your ISP will need to create an A record (for sbs.tarpondscleanup.ca, or some such) that points to your SBS's fixed IP address (whatever that is), and then have them establish an appropriate rDNS record which resolves that same fixed IP address to sbs.tarponscleanup.ca. You might also like to consider having your ISP set up an SPF record that establishes both your POP3/SMTP account with them and your SBS as kosher senders of email, to reduce the use of spammers spoofing your domain name.

C P

Canada
Member since
2/12/2007

Platinum Membership
Posts: 48

7/23/2008 01:24 PM
Thanks for your input. I am in the process of putting together steps to have have mail delivered directly to our exchange server. i will post them here shortly and I was wondering if you would give my steps a look over and see if i have covered everything. i am pretty good on most technical items except when it comes to getting mail delivered to our server properly. i will post the steps here shortly. Thanks again.

C P

Canada
Member since
2/12/2007

Platinum Membership
Posts: 48

7/23/2008 01:46 PM
Here is a set of instructions i was given on a previous chat. It is a good list of steps but is it missing anything? Like i mentioned earlier i have never worked on setting up exchange other than having pop3 pull down the mail. ok, first of all you need to create an A (Host) Record for your external domain name, that points your servers public IP address. for example, if you have a public IP of xxx.xxx.xxx.xxx then you need to get your ISP or dns administrator to create a new A record SMTP or MAIL or anything you like in your dns zone for this IP address. once done you should be able to perform an nslookup from a cmd prompt to resolve the A record to your public IP. ie. nslookup smtp.domain.com smtp.domain.com xxx.xxx.xxx.xxx You can try this now on any domain name you like, perform an nslookup on www.smallbizserver.net and see the result. C:\Program Files\Support Tools>nslookup www.smallbizserver.net Server: mydns.domain.local Address: 192.168.10.4 Non-authoritative answer: Name: www.smallbizserver.net Address: 82.94.217.243 Now, you need to change the MX configuration. The MX record is simply a pointer, that tells mail servers where to deliver your mail. It points to an A record. The A record then points to your server. To view an MX record go into CMD C:\Program Files\Support Tools>nslookup Default Server: mydns.domain.local Address: 192.168.10.4 > set type=mx > microsoft.com Server: mydns.domain.local Address: 192.168.10.4 Non-authoritative answer: microsoft.com MX preference = 10, mail exchanger = mailc.microsoft.com microsoft.com MX preference = 10, mail exchanger = maila.microsoft.com microsoft.com MX preference = 10, mail exchanger = mailb.microsoft.com microsoft.com nameserver = ns5.msft.net microsoft.com nameserver = ns1.msft.net microsoft.com nameserver = ns2.msft.net microsoft.com nameserver = ns3.msft.net microsoft.com nameserver = ns4.msft.net maila.microsoft.com internet address = 131.107.115.212 maila.microsoft.com internet address = 205.248.106.64 mailb.microsoft.com internet address = 205.248.106.30 mailb.microsoft.com internet address = 131.107.115.215 mailc.microsoft.com internet address = 205.248.106.32 mailc.microsoft.com internet address = 131.107.115.214 ns1.msft.net internet address = 207.68.160.190 ns2.msft.net internet address = 65.54.240.126 ns3.msft.net internet address = 213.199.161.77 ns4.msft.net internet address = 207.46.66.126 ns5.msft.net internet address = 65.55.238.126 From this output we can see that Microsoft have 3 MX records and that they go to maila mailb mailc all in the microsoft.com domain. Dont worry too much about the preferences at this point. So what you need to do is get your MX record changed to the A record we created first. Once this has happened all mail that is sent to your domain will be forwarded onto smtp.domain.com For your server to receive mail, you need to open TCP port 25 on the external interface of your router and forward it to the external IP address of your SBS box. You will need to rerun the CEICW to tell it that mail is delivered directly to your server, and this will create the correct rules in ISA to publish the exchange server. You may want to create the A record, and publish the server before changing the MX record so you can test the configuration. To test a connection to your mail server, from an external location go into cmd and type telnet smtp.domain.com 25 or telnet xxx.xxx.xxx.xxx 25 what this command does is ask your pc to create a session with the smtp svc (port 25) at the specefied fqdn or IP address. you should then see an output like this 220 mail01.microsoft.com Microsoft ESMTP MAIL Service ready at Tue, 29 Jan 2008 05:54:53 -0800 if you see this kind of output then the publishing is successful and you can proceed to change your MX record. Note that DNS replication can take up to 48 hours worldwide, so you might want to do it on a friday night so it is ready for monday morning.

Steve Moss User is Offline

Telford, U.K.
Member since
8/30/2006

Registered Users
Posts: 104

7/23/2008 03:22 PM
Yes, those instructions are fine. It is the organisation who manages your DNS records that will create/change your A and MX records. It is normally your ISP who will do this (unless they have delegated control to you and provided you with the necessary 'control panel' interface). It is then your responsibility to open up TCP port 25 in your firewall to point to your SBS's internal IP address, and to re-run the CEICW. Do bear in mind, though, that none of this imapcts the mail delivery problem you have - you will still need the requisite rDNS record to be created to solve that issue.

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