Fedora + Dovecot - only one client can connect per user?

[Alexander Dalloz]

Am 20.06.2016 um 04:15 schrieb Thomas Cameron:
> Howdy -

Hi Thomas,

> I am running dovecot-2.2.24-1.fc23.x86_64 on Fedora 23. It's up to date
> as of last night.
>
> When I log in from a desktop using Thunderbird on Linux, my Android
> phone (Nexus 6P) stops receiving mail. It happens if I'm on my laptop or
> my desktop.
>
> My wife has the same problem using Thunderbird on Windows. If she leaves
> the house and forgets to shut down her MUA, her phone can't retrieve
> messages.
>
> Is this expected behavior? Can I change it? I feel like it's pretty
> common for folks to have multiple devices which access the same mail
> account. Between phones, tablets, PCs, etc., this seems like a pretty
> common scenario.

no, that's not to be expected and should work pretty well.

> It's a pretty vanilla setup:
>
> [root at wintermute ~]# dovecot -n
> # 2.2.24 (a82c823): /etc/dovecot/dovecot.conf
> # OS: Linux 4.4.4-301.fc23.x86_64 x86_64 Fedora release 23 (Twenty Three)
> 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 =
> }
> passdb {
>   driver = pam
> }
> ssl = required
> ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
> ssl_cipher_list = PROFILE=SYSTEM
> ssl_key = </etc/pki/dovecot/private/dovecot.pem
> userdb {
>   driver = passwd
> }

# 2.2.24 (a82c823): /etc/dovecot/dovecot.conf
# OS: Linux 4.5.5-300.fc24.x86_64 x86_64 Fedora release 24 (Twenty Four)

Used an F24 test VM which came up with the same Fedora default dovecot 
configuration. I am a bit surprised that your's provides access to mail 
though it has no configuration where the mailbox is located on the 
drive: "mail_location" is empty as well "location" in the inbox namespace.

What is being logged in /var/log/maillog when the access fails? My test 
system did log

Jun 20 20:37:36 fedora24 dovecot: imap-login: Login: user=<dalloz>, 
method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, mpid=13441, secured, 
session=<6G6V/7k1FNV/AAAB>
Jun 20 20:37:36 fedora24 dovecot: imap(dalloz): Error: User 
initialization failed: Namespace '': Mail storage autodetection failed 
with home=/home/dalloz
Jun 20 20:37:36 fedora24 dovecot: imap: Error: Invalid user settings. 
Refer to server log for more information.

Made it working by adding

mail_location = mbox:~/mail:INBOX=/var/mail/%u

to /etc/dovecot/conf.d/10-mail.conf.

2 parallel IMAP logins then were no problem at all. The default limit on 
your Fedora is

# doveconf | grep mail_max_userip_connections

> Thanks!
> Thomas

Kind regards

Alexander