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Question about Backup MX user verification
Question asked by Linda Pagillo - 3/21/2016 at 7:38 AM
Unanswered
Hello everyone. I noticed something that happened over the weekend when I was migrating a Smartermail installation from one server to another. Prior to the migration, I set up one of my other Smartermail servers as a backup MX for my primary server that I was migrating. Since my primary server is a Smartermail server, I enabled Smartermail Gateway Mode on the backup MX. I set it to use Web Service as the user verification type.I noticed that when I took my primary server down and tested sending to it, I received bounces stating 550 - no such user here. I believe this happened because since my primary server was down, the user verification couldn't happen, therefore, the messages bounced. Am I correct in this assumption? If yes, can someone tell me a way around this besides using no verification? Also, if I'm correct in my assumption, what is the point/value of Web Service verification if it doesn't work if the primary server is down? Thanks!
Linda Pagillo
Mail's Best Friend
Email: linda.pagillo@mailsbestfriend.com
Web: www.mailsbestfriend.com
Authorized SmarterTools Reseller
Authorized Message Sniffer Reseller
 

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Linda Pagillo Replied
Anyone? :)
Linda Pagillo
Mail's Best Friend
Email: linda.pagillo@mailsbestfriend.com
Web: www.mailsbestfriend.com
Authorized SmarterTools Reseller
Authorized Message Sniffer Reseller
 
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Merle Wait Replied
That is a good question....
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Matt Petty Replied
Employee Post
User verification via a web service would require the primary to be up, since that's how the user verification is done. Gateways are meant to "assist" the primary mail server. Using user verification this way would require the gateway to cache or pull all these values from the primary while it is still up in order for this to work, we currently do not do this.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
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Merle Wait Replied
Thank you for your response.... 
So.. if I know that for whatever reason.. the primary becomes unavailable... either inbound gateway has to be switched to a backup service mode.   Correct?  But here is no auto-detection from the gateway to primary  - or notification that the gateway can not reach the primary.... :(
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Matt Petty Replied
Employee Post
Correct. However, generally backup mx servers are kept as backup mx servers, as far as I know people don't really hot swap between Backup and Gateway modes.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
0
Linda Pagillo Replied
Thanks for your response Matt. I have another question... it's my understanding that backup MX servers can be used as a kind of store and forward service in the event that the primary server is unavailable. I currently use Smartermail backup MX servers for this purpose. However, are you saying that if I'm going to use a Smartermail server as a backup MX, I need to choose no verification in order for it to work?
Linda Pagillo
Mail's Best Friend
Email: linda.pagillo@mailsbestfriend.com
Web: www.mailsbestfriend.com
Authorized SmarterTools Reseller
Authorized Message Sniffer Reseller
 
0
David Barker Replied
Hi Matt just for clarification so I understand correctly what you are saying. ....

I am assuming (maybe incorrectly) the purpose of a Backup MX server is to catch email in case the Main MX server fails.

If user validation is setup so the Backup MX queries the Main MX server to know who to accept mail for, but when the Main MX server goes down, the Backup MX server does not know who to accept mail for and so responds that the user does not exist.

My question is what then is the purpose of a Backup MX server ?

Email : david.barker@mailsbestfriend.com
Web : www.mailsbestfriend.com
Office : 866.919.2075
1
Matt Petty Replied
Employee Post
I've talked to Bryon about this and we will be classifying this as a bug. Backup MX without the ability to verify users without the Primary really hampers its ability to function as a backup. 

Currently the backup mx can only function as a true backup (without the primary available) if the user verification is off.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
0
Matt Petty Replied
Employee Post
See below.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
0
Webio Replied
Hello,
 
what version of SM was one which you  where migrating? I was experiencing similar issues with some older versions. I was sending few support tickets about no such user here issue and from some time now I'm not experiencing this anymore (emails are being delivered when main server is back online and no such user here is not returning during primary server startup process). On my end I'm using Domain Forward -> All Domains with user verification using web service. I can't use Backup MX because my main server is not listed as a MX server.
 
Regards
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David Barker Replied
I think the answer is simply that in the case the Main MX server is not available to the Backup MX, user verification is disabled on the Backup MX
Email : david.barker@mailsbestfriend.com
Web : www.mailsbestfriend.com
Office : 866.919.2075
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Linda Pagillo Replied
It was the latest 14 version.
Linda Pagillo
Mail's Best Friend
Email: linda.pagillo@mailsbestfriend.com
Web: www.mailsbestfriend.com
Authorized SmarterTools Reseller
Authorized Message Sniffer Reseller
 
0
Merle Wait Replied
hi Webio, I am a little confused by the comment:  "I can't use Backup MX because my main server is not listed as a MX server."....
Since I never used SM in a true backup capacity, and only gateway mode(which I now understand.. is not so bright of an idea either... )   I wasn't aware the main server had to be listed in the DNS as MX record.  I was just using the I/P address of the main server....    AND more to the point as well.... the back-up AND current gateway servers take the emails and deliver them via internal I/P address 
 
Example:  
DNS MX: 122.122.122.122 --->gateway --> 192.168.52.52 --> MainServer
(true the main server has a public address too, but we choose to route the email internally to it).   All servers are 14.x
 
 
Not arguing... just trying to learn ... {which apparently I have a long way to go :) }
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Webio Replied
Backup MX with higher priority number will try to deliver messages to domains MX servers with lower MX priority number and thats why main SM instance must be placed in domains MX records. Domain Forwarding is different because it forwards emails to certain mail server which address has been set in SmarterMail gateway configuration.

Edit:
https://portal.smartertools.com/kb/a2668/configure-smartermail-as-a-backup-mx-server.aspx

point 14.
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Webio Replied
Then maybe this is related to Backup MX functionality. I'm using only Domain Forwarding option which works fine from some time now.

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