Solved

Email Server Setup Problems

Posted on 2011-03-16
6
427 Views
Last Modified: 2013-11-10
We run a web and email hosting service for small businesses in the area. One of our customers is complaining of undelivered emails from certain domains (linkedin.com, dyndns.com, salesforce.com). Our server hosts multiple domains, including our own. I tested that the domains in question could email our server by signing for accounts myself and receiving the confirmation emails. Everything worked correctly. There is no entry in /var/log/maillog for the emails in question.

Why would these emails be delivered to one account (hockson.com) on a server, but not another account (castillolanguageservices.com)? Hockson.com is the primary domain for the server.

I also have a message in the mail queue stating that a server configuration error occurred (4.3.5). I am using Postfix 2.6.5 on Fedora 12. The needed firewall ports are open (ie: 25 plus the ports for POP and IMAP).
0
Comment
Question by:tysonk
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 2
6 Comments
 
LVL 6

Assisted Solution

by:de2Zotjes
de2Zotjes earned 500 total points
ID: 35155648
The most likely explanation (with the info provided) is that the name resolving of the MX record for the 2 domains is different. That checks out when I dig the domains:

~$ dig MX castillolanguageservices.com

; <<>> DiG 9.7.1-P2 <<>> MX castillolanguageservices.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7230
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 0

;; QUESTION SECTION:
;castillolanguageservices.com.	IN	MX

;; ANSWER SECTION:
castillolanguageservices.com. 300 IN	MX	0 69.57.170.228.

~$ dig MX hockson.com

; <<>> DiG 9.7.1-P2 <<>> MX hockson.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32198
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0

;; QUESTION SECTION:
;hockson.com.			IN	MX

;; ANSWER SECTION:
hockson.com.		3600	IN	MX	0 smtp.hockson.com.

~$ dig smtp.hockson.com

; <<>> DiG 9.7.1-P2 <<>> smtp.hockson.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47527
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 0

;; QUESTION SECTION:
;smtp.hockson.com.		IN	A

;; ANSWER SECTION:
smtp.hockson.com.	3600	IN	CNAME	hockson.com.
hockson.com.		1800	IN	A	69.57.170.228

~$ dig -x 69.57.170.228

; <<>> DiG 9.7.1-P2 <<>> -x 69.57.170.228
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4971
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1

;; QUESTION SECTION:
;228.170.57.69.in-addr.arpa.	IN	PTR

;; ANSWER SECTION:
228.170.57.69.in-addr.arpa. 86400 IN	PTR	webhost.hockson.com.

Open in new window

Perhaps the mentioned mail senders will not forward to places where the reverse record points to another domain?

Your mail queue is concerned with mail you are forwarding through this box, so unless it concerns a mail addressed to the bad domain it is probably not related. If it is for the non functioning domain, could you please post the entire message here?

0
 

Author Comment

by:tysonk
ID: 35159544
I have completed further testing on this issue and have been able to get email from DynDNS.com to come through castillolanguageservices.com. However, I am still unable to receive mail from LinkedIn.com. I can receive mail from LinkedIn at Hockson.com, but not castillolanguageservices.com. I managed this by altering the smtpd_recipient_restrictions configuration item to permit_mynetworks, reject_unath_pipelining, permit_auth_destination.

Commenting on your suggestion:
I'm not sure I understand what you mean when you say the name resolving is different. Doesn't your output show the same IP for both domains? Shouldn't this pointed to the same server then? If so, why is that it can find the server for one domain, but not the other?
0
 

Author Comment

by:tysonk
ID: 35159549
Also...there is no traffic in the logs, nor any postmaster notice generated, for the missing emails.
0
Visualize your virtual and backup environments

Create well-organized and polished visualizations of your virtual and backup environments when planning VMware vSphere, Microsoft Hyper-V or Veeam deployments. It helps you to gain better visibility and valuable business insights.

 
LVL 6

Accepted Solution

by:
de2Zotjes earned 500 total points
ID: 35159873
The name resolving is different because the way you get to an ip address is different. Another difference is that the reverse resolving will yield an address in the hockson.com domain.

As for no traffic in the logs, that is an indication the sender machines are unwilling to deliver mail to your box.

Afaik the correct content for an MX record is the name of the machine accepting mail for that entity, so perhaps you should try changing the MX for castillo...com:
castillolanguageservices.com MX webhost.hockson.com.

The downside of playing with dns is that it takes a long time to propagate through the world. Have you contacted the postmaster at linkedin.com with the question? That might yield more insight into what is going on.

0
 

Author Comment

by:tysonk
ID: 35160466
So...the MX record for castillolanguageservices.com should be smtp.hockson.com or webhost.hockson.com??
0
 

Author Comment

by:tysonk
ID: 35160530
I got it. Set all MX records to smtp.hockson.com. Thank you sooooo much for you assistance.
0

Featured Post

Three Reasons Why Backup is Strategic

Backup is strategic to your business because your data is strategic to your business. Without backup, your business will fail. This white paper explains why it is vital for you to design and immediately execute a backup strategy to protect 100 percent of your data.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Workplace bullying has increased with the use of email and social media. Retain evidence of this with email archiving to protect your employees.
Sometimes clients can lose connectivity with the Lotus Notes Domino Server, but there's not always an obvious answer as to why it happens.   Read this article to follow one of the first experiences I had with Lotus Notes on a client's machine, my…
Familiarize people with the process of retrieving data from SQL Server using an Access pass-thru query. Microsoft Access is a very powerful client/server development tool. One of the ways that you can retrieve data from a SQL Server is by using a pa…
To show how to generate a certificate request in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.:  First we need to log into the Exchange Admin Center. Navigate to the Servers >> Certificates…

615 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question