Deafness

[Steffan Cline]

Ok, I think I have come a little further.

When dovecot stops accepting connections, I checked netstat and found this:

[root at hosting1 ~]#  netstat -an | grep 993
tcp        0      0 0.0.0.0:993                 0.0.0.0:*                   LISTEN      
tcp        0      0 65.39.x.x:993            184.101.x.x:36351        SYN_RECV    
tcp        0      0 65.39.x.x:993            107.212.x.x:51487        SYN_RECV    
tcp        0      0 65.39.x.x:993            107.212.x.x:51488        SYN_RECV    
tcp        0      0 65.39.x.x:993            184.101.x.x:44650        SYN_RECV    

This told me it wasn’t too many connections causing dovecot to be unresponsive. So then I tried via telnet.

Dovecot seems to accept connections but then just sits there and does nothing. I used the appropriate commands to try and initiate a login but nothing happens. Typing any commands at all produce no response from dovecot.

I then do a “service dovecot restart” and then telnet again and get this:

* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready.

To me this suggests that dovecot is jammed up somehow.


I then check in /var/log/maillog and it shows no dovecot entries to indicate a connection.

I look in /etc/dovecot and see a dozen conf file. Without reading all the docs, is there any one in particular I can find the verbose logging?

What else can I check? Everything was fine until just a couple days ago.

This is a SERIOUS issue as I discovered it can be the root cause of a server going down.

In my config I use z-push with apache to do active sync with my iPhone.

The iPhone connects via z-push/apache and then to dovecot. The connection is stale so eventually with the phone continuously trying to connect and z-push can’t connect to dovecot, the apache processes eat all the RAM until processes crash from no memory.

Any help at this point is appreciated.


Thanks,
Steffan Cline
steffan at hldns.com
602-793–0014







On 7/28/15, 3:21 PM, "dovecot on behalf of Steffan Cline" <dovecot-bounces at dovecot.org on behalf of steffan at hldns.com> wrote:

>Permissions to the logs are fine. In /var/log/maillog I do see dovecot logging in there but nothing that indicates why there’s a failure.
>
>The one thing I thought of is if there’s too many connections but I am using a firewall that blocks excessive attempts but that’s fine. Netstat shows a bunch of CLOSE_WAIT though.
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>I’ll try the debug level and see what I find.
>
>Thanks,
>Steffan Cline
>steffan at hldns.com
>602-793–0014
>
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>
>
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>On 7/28/15, 11:53 AM, "Managed Pvt nets" <mpn at icabs.co.zw> wrote:
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>>
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>>On 28/07/2015 7:07:44 PM, "Steffan Cline" <steffan at hldns.com> wrote:
>>
>>>
>>>There’s nothing visible in the logs.
>>You need to check the permissions for your logs. Increase debug level
>>>
>>>Suggestions of what to check for?
>>The logs. Do command line tests, share what you are getting.
>>
>>M.
>>
>