Issue with one user only, exceeding connections

Paul Kudla (SCOM.CA Internet Services Inc.) paul at scom.ca
Thu Jun 9 11:37:10 UTC 2022


ok the idle connection per folder is a factor

however in thunderbird i believe it defaults to 2 simultanious connections

mine is set to 5

in thunderbird see

The solution is to reduce the maximum number of connections in 
Thunderbird. This can be done from Edit > Account Settings > Server 
Settings (under the mail account for which the setting should be 
modified) > Advanced > Maximum Number of server connections to cache.

I dont know of anything that would get it to 500?

as for outlook idle was not / is not supported past 2010 (if even that) 
you need to go into

file --> options --> advanced --> send/receive

all you can change in there is the timing which defaults to 30 minutes, 
i recommend 3 or 5

I am unaware of how outlook handles physical connections (maybe 
registery?) and google revieled nothing, outlook since 2010 just does 
not support imap, microsofts way of forcing everyone onto exchange / 
outlook 365

377,000 hits last time i googled imap issues in outlook.

Best suggestion is to run

# ps -axww | grep imap
25500  -  S          0:00.57 imap: [paul at hiscomputer.ca 172.97.150.95 
IDLE] (imap)
25530  -  S          0:00.36 imap: [paul at hiscomputer.ca 172.97.150.95 
IDLE] (imap)
26014  -  I          0:00.39 imap: [rcooke at tnky.ca 172.97.128.227 IDLE] 
(imap)
26018  -  I          0:00.38 imap: [rcooke at tnky.ca 172.97.128.227 IDLE] 
(imap)
26210  -  I          0:00.07 imap: [spanos at scom.ca 99.238.154.160 IDLE] 
(imap)
38911  -  S          0:00.17 imap: [marilynlally at scom.ca 142.188.149.199 
IDLE] (imap)
38912  -  S          0:00.13 imap: [marilynlally at scom.ca 142.188.149.199 
IDLE] (imap)
41306  -  S          0:00.73 imap: [ed.hanna at dssmgmt.com 204.237.48.37 
IDLE] (imap)
41312  -  S          0:00.63 imap: [ed.hanna at ekst.ca 204.237.48.37 IDLE] 
(imap)
45232  -  I          0:00.23 imap: [rcooke at tnky.ca 172.97.128.227 IDLE] 
(imap)
55504  -  I          0:00.16 imap: [rcooke at tnky.ca 172.97.128.227 IDLE] 
(imap)

which shows all imap connections and from where

if you are overflowing 500+ connections then it has to show up here.


Happy Thursday !!!
Thanks - paul

Paul Kudla


Scom.ca Internet Services <http://www.scom.ca>
004-1009 Byron Street South
Whitby, Ontario - Canada
L1N 4S3

Toronto 416.642.7266
Main 1.866.411.7266
Fax 1.888.892.7266
Email paul at scom.ca

On 6/8/2022 6:41 PM, Jeremy Schaeffer wrote:
> Ahhh, Ok, I did not know that and now that makes sense. I did not 
> realize it held a open connection for each folder. I increased that and 
> I will see what happens. I wonder if that will also effect the outlook 
> issues. Thanks! - Jeremy
> 
> On 6/8/2022 14:28, Frank-Ulrich Sommer wrote:
>> I think if IMAP IDLE is used you need one connection per folder. If I 
>> remember correctly at least either Thunderbird or K9 Mail (I'm using 
>> both too) use one connection per selected directory. Simply increasing 
>> the number of connections was the easiest solution as I only have very 
>> few users too.
>>
>> Regards
>> Frank
>>
>> Am 8. Juni 2022 21:14:23 MESZ schrieb Jeremy Schaeffer 
>> <kb9mfd at phonesplus.biz>:
>>
>>     I keep having this issue with one user, and I have to restart dovecot
>>     several times a day to clear it. What I have is a postfix / dovecot mail
>>     server (Centos 7) and about a dozen users. All mailboxes are imap ssl. I
>>     monitor about 4 mailboxes on my computer and tablet. I use Thunderbird
>>     on the computer (cache connections at 2) and K9 on the tablet, but one
>>     user of the four I keep getting "Maximum number of connections from
>>     user+IP exceeded" and I have the maximum at 50
>>     "(mail_max_userip_connections=50)" so its hard for me to believe I am
>>     actually exceeding it unless dovecot/client is not dropping connections
>>     and keeps starting new ones until it reaches the maximum, but again,
>>     only for one user, even though I am monitoring 4 on the same devices.
>>     Any idea how to troubleshoot this? I don't know if I should be looking
>>     at dovecot or the clients, or what I need to look for. It's been going
>>     on since I put this server in use over a year ago. I also have issues
>>     with Outlook clients disconnecting, just outlook, is there any
>>     recommended settings to make Outlook work smoother?
>>
>>     Thanks! - Jeremy
>>
>>     Config -
>>
>>     # 2.2.36 (1f10bfa63): /etc/dovecot/dovecot.conf
>>     # OS: Linux 3.10.0-1160.11.1.el7.x86_64 x86_64 CentOS Linux release
>>     7.9.2009 (Core)
>>     # Hostname: ***
>>     auth_mechanisms = plain login
>>     debug_log_path = /var/log/dovecot_debug.log
>>     first_valid_gid = 500
>>     last_valid_gid = 600
>>     last_valid_uid = 600
>>     listen = *
>>     mail_location = maildir:~/Maildir
>>     mbox_write_locks = fcntl
>>     namespace inbox {
>>         inbox = yes
>>         location =
>>         mailbox Drafts {
>>           special_use = \Drafts
>>         }
>>         mailbox Junk {
>>           special_use = \Junk
>>         }
>>         mailbox Sent {
>>           special_use = \Sent
>>         }
>>         mailbox "Sent Messages" {
>>           special_use = \Sent
>>         }
>>         mailbox Trash {
>>           special_use = \Trash
>>         }
>>         prefix = INBOX.
>>         separator = .
>>     }
>>     passdb {
>>         driver = pam
>>     }
>>     pop3_uidl_format = %f
>>     protocols = imap lmtp
>>     service auth {
>>         unix_listener /var/spool/postfix/private/auth {
>>           group = postfix
>>           mode = 0660
>>           user = postfix
>>         }
>>     }
>>     service imap-login {
>>         inet_listener imap {
>>           port = 143
>>         }
>>         inet_listener imaps {
>>           port = 993
>>           ssl = yes
>>         }
>>         process_min_avail = 1
>>         service_count = 0
>>     }
>>     service imap {
>>         process_limit = 1024
>>     }
>>     service lmtp {
>>         unix_listener lmtp {
>>           mode = 0666
>>         }
>>     }
>>     ssl = required
>>     ssl_cert = <***
>>     ssl_cipher_list = ECDHE-RSA-CHACHA20-POLY1305:ALL:!LOW:!SSLv2:!EXP:!aNULL
>>     ssl_key =  # hidden, use -P to show it
>>     ssl_prefer_server_ciphers = yes
>>     userdb {
>>         driver = passwd
>>     }
>>     protocol imap {
>>         mail_max_userip_connections = 50
>>     }
>>
>> -- Diese Nachricht wurde von meinem Android-Mobiltelefon mit K-9 Mail 
>> gesendet.
> 
> -- 
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