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Having some bad mail server problems

Posted on 2014-11-13
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Last Modified: 2014-11-14
Hi guys,

Could use some help here. We've been having users complain that their email is either bouncing back to them or they get message delayed emails and finally it bounces back. I checked all the usual things like reversedns, blocklists, etc, but it continues to happen. Currently, if I look in the queue I see a few 421 4.2.1 errors and the message keep retrying. We do have two Interner connections here and the mail could go out on both, but the DNS is set up correctly.

Any help would be appreciated! I also ran the Microsoft Remote connection tests and it passed on both IP's:


      Performing Outbound SMTP Test
       The outbound SMTP test was successful.
       
      Additional Details
       
Elapsed Time: 19372 ms.
       
      Test Steps
       
      Attempting reverse DNS lookup for IP address 40.141.69.66.
       The Microsoft Connectivity Analyzer successfully resolved IP address 40.141.69.66 via reverse DNS lookup.
       
      Additional Details
      Performing Real-Time Black Hole List (RBL) Test
       Your IP address wasn't found on any of the block lists selected.
       
      Additional Details
       
      Test Steps
      Performing Sender ID validation.
       Sender ID validation was performed successfully.
       
      Additional Details
       
      Test Steps

Our mail server would be mail.orbuscompany.com

Thanks!
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Question by:OrbusLLC
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9 Comments
 
LVL 44

Expert Comment

by:Amit
ID: 40440638
What is the next hop after Exchange server?
Do you have any email gateway after Exchange server?
Error clearly indicates DNS issue. Are you running Exchange on VM? If yes, check VLAN configuration also.
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LVL 10

Expert Comment

by:tmoore1962
ID: 40440694
are your two internet connections in fail over or load balance.  Are the IP addresses for both ISP listed in MX record with the correct priority if they're failover?  You would also probably have to have them configured in the spf record as well for testing remove one of the internet connections (esp if not listed on mx records)
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LVL 44

Expert Comment

by:Amit
ID: 40440717
Focus on next hop, sometime ISP changes IP's without updating customer. Ask your ISP.
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Author Comment

by:OrbusLLC
ID: 40440801
We are using Postini right now as the in between. I have all IP's in the SPF and the circuits are failover using DNS Made Easy.
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LVL 44

Expert Comment

by:Amit
ID: 40440840
then focus on postini. restart postini and check again.
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Author Comment

by:OrbusLLC
ID: 40440868
Postini is a spam service in the cloud provided by Google.
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LVL 44

Expert Comment

by:Amit
ID: 40440887
then call Google and tell them about this issue you are facing. Before that you can do nslookup for you Exchange server ip's as well. just to check, if DNS records for Exchange server exist properly or not.
0
 

Author Comment

by:OrbusLLC
ID: 40443131
Looks like it has to do with our Sonicwall and DNS. I have the DNS record set for 40.141.69.67, but the mailserver is showing the IP as 40.141.69.66 which is causing issues. Can someone guide me into making the correct NAT entry on the Sonicwall?
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LVL 44

Accepted Solution

by:
Amit earned 1000 total points
ID: 40443258
As I said it is a DNS issue. I also mentioned to focus on next hop, which is Sonicwall in your case. For sonic wall create a new question.
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