1 Topic by recurvered

  • recurvered
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  • Posts: 2

Topic: Postfix/Thunderbird Lost Connection after connect

==== Required information ====
- iRedMail version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Linux/BSD distribution name and version:
- Related log if you're reporting an issue:
======== Required information ====
- iRedMail version: 0.8.5
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MYSQL
- Linux/BSD distribution name and version: DEBIAN Wheezy
- Related log if you're reporting an issue:  https://gist.github.com/anonymous/7810444  <-- Main.cf
====

(Removed the domain name from the main.cf but that should be setup correctly as it works on 99% of our machines)

At work I have a server setup running iRedMail (mysql), and I'm having a slight problem that I"m hoping you good people here can help me fix.

So we are currently using this system as a primary mail server for about 300 remote users (POS machines), we do also use this server for some internal stuff (voicemail, emailing scanned documents from some of our printers). The remote users use thunderbird to email off reports every night and for the most part it has worked flawlessly  but almost every night we have one or two remote users who are not able to connect, when searching for their ip address in the postfix logs I see

Lost Connection after connect ....

When I remote into their machine it always seems to be random what works and doesn't, sometimes I am able to send off an email and then it loses connection, sometimes they are still able to connect to the server to receive mail but cannot send and other times it loses connection to the server all together and I am no longer able to connect at all on those machines. I have fail2ban installed but their addresses are not in any jails.

I have tried my hand at googling the problem and implementing those fixes from here
http://www.postfix.org/STRESS_README.html

but it still happens every night with one or two machines.

Any help or insight you can give me I would greatly appreciate it.

thanks,

----

Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

2 Reply by ZhangHuangbin

  • ZhangHuangbin
  • ZhangHuangbin
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  • Registered: 2009-05-06
  • Posts: 31,091

Re: Postfix/Thunderbird Lost Connection after connect

Am i right that you mean lost "IMAP" connection? Or smtp connection?

I guess it reaches max IMAP connection if your mail clients access mailbox via IMAP protocol. Could you please show me output of command "dovecot -n"?

3 Reply by recurvered

  • recurvered
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Re: Postfix/Thunderbird Lost Connection after connect

Thanks for the reply,

The computers in question kind of mix it up, two of them they still had an imap connection but were unable to send out any emails. The other few computers in question would lose both and thunderbird would be unable to connect to the server at all.

Here is the result of dovecot -n

https://gist.github.com/anonymous/7828035

4 Reply by ZhangHuangbin

  • ZhangHuangbin
  • ZhangHuangbin
  • iRedMail Developers
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  • Registered: 2009-05-06
  • Posts: 31,091

Re: Postfix/Thunderbird Lost Connection after connect

Dovecot config file looks just fine, and it allows max to 500 concurrent imap login process:

service imap-login {
  process_limit = 500
  service_count = 1
}

Were the IP addresses of your clients/computers blocked in iptables when the issue happen? Do you have Fail2ban service running? If so, it might be a good idea to stop and disable it for some days to see whether this issue happens again or not.