1 Topic by samtech (edited by samtech 2016-05-28 18:33:17)

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Topic: What are Timeouts (inbound) and Connections lost (inbound)

======== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.5.1
- Linux/BSD distribution name and version: Debian 8
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): SQL
- Web server (Apache or Nginx): Apache
- Manage mail accounts with iRedAdmin-Pro? Yes
- Related log if you're reporting an issue:
====

In daily logwatch of my mail server if see such entries

      613   Connections             
       13   Connections lost (inbound)
      613   Disconnections   
      635   Removed from queue     
      328   Delivered               
      476   Sent via SMTP           
        8   Forwarded               

       27   Timeouts (inbound)     
        2   SMTP dialog errors     
       33   SASL authenticated messages

My concern is with entried marked with RED color.
What are those timeouts and how to avoid them ?

----

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2 Reply by ZhangHuangbin

  • ZhangHuangbin
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Re: What are Timeouts (inbound) and Connections lost (inbound)

I'm afraid that you have to figure it out with Postfix log file.

3 Reply by samtech (edited by samtech 2016-05-31 16:38:14)

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Re: What are Timeouts (inbound) and Connections lost (inbound)

What i should look into Postfix log ?

I grep for timeout and got following

samtech@mail:~$ sudo tail -n 1000 /var/log/mail.log | grep imeout
[sudo] password for samtech: 
May 31 12:50:13 mail postfix/smtpd[1509]: timeout after END-OF-MESSAGE from mail.mygroup.org[127.0.0.1]
May 31 12:50:13 mail postfix/smtpd[1516]: timeout after END-OF-MESSAGE from mail.mygroup.org[127.0.0.1]
May 31 12:50:13 mail postfix/smtpd[1494]: timeout after END-OF-MESSAGE from mail.mygroup.org[127.0.0.1]

4 Reply by ZhangHuangbin

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Re: What are Timeouts (inbound) and Connections lost (inbound)

*) "Connection" and "Disconnection" are very normal, each sender needs to connect to your server to deliver email, then disconnect.
*) "Timeout" usually caused by temporary network issue, or bad clients.

Don't panic -- unless you find detailed error in Postfix log file. smile

5 Reply by samtech

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Re: What are Timeouts (inbound) and Connections lost (inbound)

Few days ago we moved from test phase to production, now below are the statistics

14223   Connections             
     3057   Connections lost (inbound)
        1   Connections lost (outbound)
    14224   Disconnections         
    19850   Removed from queue     
    14180   Delivered               
    14844   Sent via SMTP           
      654   Forwarded               
        4   Deferred               
       11   Deferrals               
       40   Bounced (remote)       
        1   Expired and returned to sender
       56   Notifications sent     

       11   Connection failures (outbound)
       22   Timeouts (inbound)
      102   Illegal address syntax in SMTP command
       85   Hostname verification errors (FCRDNS)
        9   SMTP protocol violations
        2   PIX workaround enabled 
      982   SASL authenticated messages
        8   Host offered TLS       


You can see value for 'Connections lost (inbound)' is too high.
That's why i am worried. BTW what does it mean?

6 Reply by ZhangHuangbin

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Re: What are Timeouts (inbound) and Connections lost (inbound)

Before i answer this question, i wonder what you think about these messages?

7 Reply by samtech

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Re: What are Timeouts (inbound) and Connections lost (inbound)

Connections lost (inbound), means incoming mails reached our server but couldn't connect vmail database.

No idea about
- Connections lost (outbound)  &
- Timeouts (inbound)

8 Reply by ZhangHuangbin

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Re: What are Timeouts (inbound) and Connections lost (inbound)

Connection lost, timeout, they're usually network problems, maybe temporary network issue.

Connection lost is usually caused due to client didn't respond the reply required by MTA (your server) and MTA waited for some time, but MTA didn't eventually get the reply, so it disconnect the connection and log a "connection lost" message.

timeout is network issue, maybe your server cannot reach the destination, maybe the receiver server blocks your smtp traffic without rejecting it. You need to pay some attention to this issue.