Dovecot does not accept new connection with error "imap-login: Error: read(anvil) failed: EOF"

[Julien Fastré]

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Hi,

First of all, thank you for the work the contributors are doing with
Dovecot ! Dovecot is doing a great job !

I am encountering a problem with a configuration and, despite my
search on the web, I do not find any solution for this problem.

Dovecot seems to stop accepting new connection. The users :

- - can not save sent messages to "Sent" folder (using Thunderbird) ;
- - can not connect or retrieve message from webmail (using sogo or
roundcube)

In the log, I see this error :


> Jun 30 13:54:53 mail dovecot: imap-login: Error: read(anvil)
> failed: EOF Jun 30 13:54:53 mail dovecot: message repeated 2 times:
> [ imap-login: Error: read(anvil) failed: EOF]

(the message may be repeated more than 2 times)

It happens... sometimes. Manually restarting the dovecot service make
the software working again.

By searching on the web, I regularly see this statement in logs :


> dovecot: auth: Error: read(anvil-auth-penalty) failed: EOF

like here : http://www.dovecot.org/list/dovecot/2010-November/054694.htm
l

But it doesn't seem to be the same problem as mine (anvil /
anvil-auth-penalty).

The problem happens during peak load. Sometimes it happens twice a
week, sometimes it may spent two month without any problem (during
holidays, I did not had any problem).


My configuration :

> # doveconf -n # 2.2.9: /etc/dovecot/dovecot.conf # OS: Linux
> 3.13.0-49-generic x86_64 Ubuntu 14.04.3 LTS login_trusted_networks
> = 10.0.3.0/24 mail_location = mbox:~/mail:INBOX=/var/mail/%u 
> mail_plugins = quota acl managesieve_notify_capability = mailto 
> managesieve_sieve_capability = fileinto reject envelope
> encoded-character vacation subaddress comparator-i;ascii-numeric
> relational regex imap4flags copy include variables body enotify
> environment mailbox date ihave namespace { list = children location
> = maildir:/var/mail-data/vhosts/%%u:INDEX=~/shared/%%u prefix =
> shared/%%u/ separator = / subscriptions = no type = shared } 
> 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
> = separator = / type = private } passdb { driver = pam } passdb { 
> args = /etc/dovecot/dovecot-ldap.conf.ext driver = ldap } plugin { 
> acl = vfile acl_shared_dict =
> file:/var/mail-data/acl_db/shared-mailboxes quota = maildir:User
> quota quota_grace = 10%% quota_rule = *:storage=2G quota_rule2 =
> Trash:storage=+100M sieve = ~/.dovecot.sieve sieve_dir = ~/sieve } 
> postmaster_address = julienfastre at cvfe.be protocols = " imap lmtp
> sieve" service auth { unix_listener
> /var/spool/postfix/private/dovecot-auth { group = postfix mode =
> 0660 user = postfix } } service lmtp { unix_listener
> /var/spool/postfix/private/dovecot-lmtp { group = postfix mode =
> 0600 user = postfix } } ssl_ca = </etc/dovecot/certificates/ca.pem 
> ssl_cert = </etc/dovecot/certificates/mail.cert.pem ssl_key =
> </etc/dovecot/certificates/mail.key.nopass.pem userdb { driver =
> passwd } userdb { args = /etc/dovecot/dovecot-ldap.conf.ext driver
> = ldap } protocol lmtp { mail_plugins = quota acl sieve } protocol
> imap { mail_max_userip_connections = 30 mail_plugins = quota acl
> imap_quota imap_acl }

As somes answer about anvil-auth-penalty may suggest it is linked with
proc capabilities, this is the limitation of the /proc

> root at mail:/home/ubuntu# ps -aux | grep anvil postfix   4568  0.0
> 0.0  27404  1596 ?        S    08:00   0:00 anvil -l -t unix -u -c 
> dovecot   5788  0.0  0.0   9280   956 ?        S    09:45   0:00
> dovecot/anvil root      5973  0.0  0.0  11748   928 pts/2    S+
> 09:57   0:00 grep --color=auto anvil root at mail:/home/ubuntu# cat
> /proc/5788/limits Limit                     Soft Limit
> Hard Limit           Units Max cpu time              unlimited
> unlimited            seconds Max file size             unlimited
> unlimited            bytes Max data size             268435456
> 268435456            bytes Max stack size            8388608
> unlimited            bytes Max core file size        0
> unlimited            bytes Max resident set          unlimited
> unlimited            bytes Max processes             257157
> 257157               processes Max open files            1024
> 4096                 files Max locked memory         65536
> 65536                bytes Max address space         268435456
> 268435456            bytes Max file locks            unlimited
> unlimited            locks Max pending signals       257157
> 257157               signals Max msgqueue size         819200
> 819200               bytes Max nice priority         0
> 0 Max realtime priority     0                    0
>  Max realtime timeout      unlimited            unlimited
> us

If it may help, dovecot is running inside an lxc container.

I would really appreciate any help. Thanks for your time !

Julien Fastré

- -- 
Julien Fastré
Champs Libres
http://www.champs-libres.coop
+32 486 540 660

Champs Libres Cooperative SCRLFS
Rue Jean Bury 23 - 4000 Liège - Belgique
BE0541.427.670
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