Delay in delivering

                               Hi Davide,

 

I found a strange behavior in Xmail for local delivery due to a DNS problem.

Let me describe first the installation.

 

-1- Xmail 1.26 configuration and binaries duplicated from a running platform
directly exposed on internet

-2- This duplicated Xmail has been installed on DMZ (behind a firewall +
NAT) : 192.168.1.100

-3- On firewall : transparent translation of port 110 and 25 to Xmail

 

I had the following problems:

-          Not all mails were going out (some of them being always in
retry), others going out.

-          2 hours for delivery of received mails (even mails sent from
local account to another local account)

 

Strange behavior:

-1- If I Stop and Start Xmail, all mails in the spool are finally delivered
immediately to mailboxes (but still problem when sending)

-2- after that, again 2 hours minimum for delivery (I can see mails in the
spool.)

-3- If I Stop and Start again Xmail, all mails in the spool are delivered
immediately to mailboxes (but still problem when sending)

=> I can't do that every 3 minutes :( and btw still mails that are in retry
mode, then after a while, in frozen state.

 

After spending time on Xmail queue (thanks to Xmail Queue Manager: GREAT)
and looking in the log, I found that Xmail had DNS problems.

I don't know why because the server is resolving Names with no problem.
(dns1 : 192.168.1.20 ; dns2 : 83.144.0.10)

Googleing  my errors, I found things about DNS recursion (my DNS server
192.168.1.20 was already accepting recursion.)

What I did is:  uncomment SmartDNSHost and put : 

"SmartDNSHost"             " 192.168.1.20:tcp"

 

Then, all the message that were not going out started finally to go out and
immediately the received mails were delivered.

 

-          Question 1:                Why do I need SmartDNSHost ?? In my
case, The server running Xmail has already DNS servers entries in its TCP/IP
configuration 

 

-          Question 2:                I think there is no link between local
delivery and outgoing mails, no ? Why Xmail is not delivering immediately
received mails, even if Xmail is having problems to send mails due to DNS
resolution ??

 

On a other network (with DMZ, Firewall, Nat), I have done the same test
(Xmail V 1.25) and reproduce this behavior that is solved immediately with
SmartDNSHost

 

No help/solution needed, I just want to understand.

 

Hope I'm clear enough,

 

Best,

 

Emmanuel Gonzalez

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