Hopefully some one here knows the answer to this and im posting in the correct section..

For some reason imap connections stop working all of a sudden... This just started in the last month. Sometimes with in 24 hours and sometimes its up for as long as 4 days but the symptom is always the same. Users are suddenly unable to access imap via iphone. Zmcontrol restart resolves the issue.

At first I thought it was connection pool exhaustion but I have raised that 3 times now currently I am at 800
zimbraImapNumThreads: 800

It was at 200 previously. This new number seems high to me as there are only 8 imap users Total.

Doing some further digging I was able to find the following error

<--
ImapSSLServer-106076] [ip=201.23.160.71;] ProtocolHandler - Exception occurred while handling connection
java.net.SocketException: Connection timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream. java:129)
at com.sun.net.ssl.internal.ssl.InputRecord.readFully (InputRecord.java:293)
at com.sun.net.ssl.internal.ssl.InputRecord.read(Inpu tRecord.java:331)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRec ord(SSLSocketImpl.java:798)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.perform InitialHandshake(SSLSocketImpl.java:1138)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHa ndshake(SSLSocketImpl.java:1165)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.startHa ndshake(SSLSocketImpl.java:1149)
at com.zimbra.cs.tcpserver.ProtocolHandler.startHands hake(ProtocolHandler.java:184)
at com.zimbra.cs.tcpserver.ProtocolHandler.run(Protoc olHandler.java:134)
at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Wo rker.run(Unknown Source)
at java.lang.Thread.run(Thread.java:662)
2013-02-21 18:23:03,387 INFO [ImapSSLServer-106076] [] ProtocolHandler - Handler exiting normally
2013-02-21 18:23:06,754 INFO [Timer-Zimbra] [] session - WaitSet sweeper: 1 active WaitSets (1 accounts) - 1 sets with blocked callbacks
--->

But Im not sure what it exactly means...

Netstat shows alot of 993 connections it seems from same address(if im reading this right)

tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:31815 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:30723 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.172:18368 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.85:31123 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:31825 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:28142 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.172:21592 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:27893 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:32514 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:30713 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:31095 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:30612 CLOSE_WAIT
tcp 0 0 ::1:52063 ::1:35892 TIME_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:29733 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.172:16429 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:33014 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.82:27951 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.168:51357 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:34567 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:31819 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.73:56997 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:34419 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.82:34326 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:32142 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:34430 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:29783 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:31652 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.168:47634 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:31552 CLOSE_WAIT
tcp 184 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.66:59080 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:29536 ESTABLISHED
tcp 184 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.73:55132 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:33595 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.82:27963 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:29029 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:28299 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:28504 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.85:31112 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.85:31088 ESTABLISHED
tcp 187 0 ::ffff:66.240.174.67:993 ::ffff:74.198.9.107:62564 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:32963 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.168:49454 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:32845 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:34376 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:29334 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:32342 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:28420 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.168:48278 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:31944 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:30960 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.73:55185 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:30653 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.85:31120 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.99:25649 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:32543 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.17.185.1:44385 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.73:57823 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:28529 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.148:51946 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.168:48204 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.172:21653 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:34432 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:27369 CLOSE_WAIT
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.172:16298 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.160.168:52686 ESTABLISHED
tcp 0 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:32707 ESTABLISHED
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:27473 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:29728 CLOSE_WAIT
tcp 185 0 ::ffff:66.240.174.67:993 ::ffff:201.23.162.79:28331 CLOSE_WAIT


How can I verify if pool exhaustion is actually taking place or if its something else.

I am currently on 6.0.10_GA_2692.F7 but would be willing to upgrade to the latest 6.x branch if it would help...

Thanks!!