- dovecot - dovecot.org

auth: Warning: DNS lookup took 1.550 s
by ML mail 05 Feb '15

05 Feb '15

Hello, I am running a dovecot and proxy server on two different virtual machines and on the dovecot proxy server I see around 5-6 times per day the following warning: Feb 03 16:15:12 auth: Warning: proxy(email(a)domain.com,xxx.xxx.xxx.xxx,<ABC123456789>): DNS lookup for mailboxserver.domain.com took 1.550 s I do not really understand how from time to time DNS queries are slow, I tried replicate this issue using dig to resolve the same DNS entry and it was always very fast. Is there any way I can debug better this issue? or is this nothing to worry about really? Regards ML

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lazy_expunge + mdbox
by fernando.figaro＠uol.com.br 05 Feb '15

05 Feb '15

Hi, I'm studying an issue related to mdbox and lazy_expunge. If it is active in the imap configuration, when you delete a message (copy to new folder + expunge old folder), a copy is also sent to the expunge namespace. I realize that is something related to mdbox and lazy_expunge_only_last_instance and found almost no references except this one (http://hg.dovecot.org/dovecot-2.2/file/24d6708cea76/TODO) lazy_expunge_only_last_instance=yes + mdbox doesn't work, because refcounts don't update immediately One other suggestion I found was to disable 'move' capability. Does anyone has other news regarding this issue ? Thanks, Fernando

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Re: auth: Warning: DNS lookup took 1.550 s
by Joseph Tam 05 Feb '15

05 Feb '15

ML mail writes: > I am not running a local DNS cache on the server. As suggested using a > local DNS cache would simply fix this issue but I am more interested to > know what is generating these slow DNS queries... As another poster has commented, a slow DNS response may not be anything related to your setup, but caused by upstream DNS service. Slow DNS response or timeouts is not uncommon, and if you're only getting 6 per day, you should count yourself lucky. If it's the same FDQN that's being delayed, you can maybe run an online DNS diagnostic -- they're may be some bum delegation or unsync'd data you can report, but it will probably not be worth your time to chase this to ground unless it's causing your client to get hung. Joseph Tam <jtam.home(a)gmail.com>

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Hitting wall at 2048 IMAP connections
by Ron Cleven 04 Feb '15

04 Feb '15

We are gradually rolling out Dovecot (IMAP only, no POP3) to our customer base. We are replicating between a pair of CentOS 7 boxes. All has been working wonderfully. However, to be sure our rollout continues to go smoothly, we put together a simple benchmark client program to fire up X persistent IMAP connections (using hundreds of mailboxes) that login, list the folders, select the INBOX, periodically FETCH an email from the INBOX, and otherwise sit in an IDLE loop. As long as we keep the number of concurrent IMAP connections under 2k, everything works fine. 2,000 processes generate a minimal load on the server. However, 2048 is a "hard limit" for number of IMAP processes on a box the way things are configured right now. The number (2048) is a bit too magical to be anything but a misconfiguration of either some kernel limit or a dovecot configuration limit. I have been unable to figure out where else to look. I have pasted in my dovecot config below along with the kernel setting for max_user_instances. Hoping someone can tell me what stupid mistake I have made or what else to check. Just an aside, we front-end this with a separate set of proxy servers that provide an SSL front-end, hence, no SSL in the dovecot config. /proc/sys/fs/inotify/max_user_instances = 4096 # 2.2.10: /etc/dovecot/dovecot.conf # OS: Linux 3.10.0-123.13.1.el7.x86_64 x86_64 CentOS Linux release 7.0.1406 (Cor e) auth_master_user_separator = * auth_mechanisms = plain login default_internal_user = sysadm default_login_user = sysadm default_vsz_limit = 512 M disable_plaintext_auth = no doveadm_password = ************** doveadm_port = 12345 imap_max_line_length = 128 k listen = * mail_gid = 2001 mail_location = maildir:~/Maildir mail_plugins = notify replication mail_uid = 2001 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 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 { args = scheme=PLAIN /z/imap/usr/master-users driver = passwd-file master = yes pass = yes } passdb { args = scheme=PLAIN username_format=%u /z/imap/usr/users driver = passwd-file } plugin { mail_replica = tcp:imap0s sieve = ~/.dovecot.sieve sieve_dir = ~/sieve sieve_max_actions = 32 sieve_max_redirects = 4 sieve_max_script_size = 1M } protocols = imap pop3 sieve service aggregator { fifo_listener replication-notify-fifo { mode = 0666 user = sysadm } unix_listener replication-notify { mode = 0666 user = sysadm } } service auth { unix_listener auth-userdb { mode = 0777 } } service doveadm { inet_listener { port = 12345 } user = sysadm } service imap { process_limit = 4096 } service managesieve-login { inet_listener sieve { port = 4190 } } service managesieve { process_limit = 4096 } service replicator { process_min_avail = 1 } ssl = no userdb { args = username_format=%u /z/imap/usr/users driver = passwd-file } protocol lda { mail_plugins = sieve notify replication } protocol imap { mail_max_userip_connections = 40 } protocol sieve { managesieve_max_line_length = 65536 }

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Corruption of index files
by Oliver Welter 04 Feb '15

04 Feb '15

Hi All, after upgrading my mail server (dovecot 1.1.7 -> 2.2.13) I get tons of messages about corrupted index files in the syslog ("Error: Corrupted transaction log" and "Warning: fscking index file .. dovecot.index". I tried flock and even dotlock, but the problems persist. The system is a VPS with an overlay filesystem which did work flawlessly with the old dovecot install and is not reporting any errors in the host machine. From time to time I get warnings about an exceeded inotify limit for the dovecot user - might this be a problem? Anybody has an idea what might be the cause those problems and how to track them down. Oliver -- Protect your environment - close windows and adopt a penguin!

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Upstart script for Poolmon
by Listas＠Adminlinux 03 Feb '15

03 Feb '15

Hi My servers are Ubuntu 14.04 and I'm needing to make a Upstart script for Poolmon. Does someone already made this and could to share with us ? Thanks! -- Thiago henrique

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Master user without pass=yes error
by Thomas HUMMEL 03 Feb '15

03 Feb '15

Hello Timo, I just tried the master user feature with a very simple setup (Dovecot v2.2.15) : !include auth-master.conf.ext -> passwd-file passdb !include auth-ldap.conf.ext -> ldap passdb (userdb prefetched) without auth_bind=yes without pass=yes I get this userdb lookup error : dovecot: auth: passwd-file(masteruser,157.99.64.42,master,<4Pgesh0OygCdY0Aq>): Master user logging in as normaluser dovecot: auth: Error: prefetch(normaluser,157.99.64.42,<4Pgesh0OygCdY0Aq>): userdb lookup not possible with only userdb prefetch dovecot: imap: Error: Internal auth failure (client-pid=10449 client-id=1) dovecot: imap-login: Internal login failure (pid=10449 id=1) (internal failure, 1 successful auths): user=<normaluser>, method=PLAIN, rip=157.99.64.42, lip=157.99.64.81, mpid=10570, TLS, session=<4Pgesh0OygCdY0Aq> with pass=yes, it works. Feb 2 17:51:24 langres dovecot: auth: passwd-file(masteruser,157.99.64.42,master,<YmjAwx0O0gCdY0Aq>): Master user logging in as normaluser Feb 2 17:51:24 langres dovecot: imap-login: Login: user=<normaluser>, method=PLAIN, rip=157.99.64.42, lip=157.99.64.81, mpid=11647, TLS, session=<YmjAwx0O0gCdY0Aq> I dont quite understand why because the documentation states that 'pass=yes' "means that Dovecot verifies that the login user really exists before allowing the master user to log in. Without the setting if a nonexistent login username is given,[...]" Here, 'normaluser' exists in the ldap passdb so, even with pass=no, I'm not supposed to be in the 'nonesxistent login username' case. Can you help ? thanks. -- Thomas Hummel | Institut Pasteur <hummel(a)pasteur.fr> | Groupe Exploitation et Infrastructure

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quote strings passed to sql
by Juan Bernhard 03 Feb '15

03 Feb '15

Hello list. I'm thinking to migrate the hole user db from system users to mysql. I already did it in a test environment, but something is annoying my OCD... I don't quote the variables username and password sent to the mysql server. I know, the mysql user that dovecot uses only has select rights, but it stills bother me, because its possible to do an useless sql code injection. Is there a way to quote that? Something like exim's quote_mysql? Saludos, Juan.

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Re: Uniqueness of dovecot mailbox-guids
by Christian Binder Stadt Freilassing 02 Feb '15

02 Feb '15

Can no one give some adivse on this issue? Thanks Christian

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LDAP: "unused" & "uid missing"
by Leander Schäfer 02 Feb '15

02 Feb '15

Does someone know what this means? It looks to me like it got the UID, yet it complains ... ? Also, why does it complain about attributes being unused, yet I use prefetch, so they will be used?! Log: [...] dovecot: auth: Debug: ldap(test(a)mydomain.tld,192.168.10.233,<Rl2CF+UNhgDAqArp>): result: mailStorageDirectory=/var/vmail mailUidNumber=2110 mailGidNumber=2110 mailQuotaStorage=10240 mailQuotaMessages=20; mailQuotaMessages,mailStorageDirectory,mailUidNumber,mailQuotaStorage,mailGidNumber unused dovecot: auth: Debug: ldap(test(a)mydomain.tld,192.168.10.233,<Rl2CF+UNhgDAqArp>): result: mailStorageDirectory=/var/vmail mailUidNumber=2110 mailGidNumber=2110 mailQuotaStorage=10240 mailQuotaMessages=20; uid missing [...] As mentioned, I use prefetch, so this is how my dovecot/dovecot-ldap.conf.ext is looking: [...] #user_attrs = mailStorageDirectory=home=%$/%u, mailStorageDirectory=mail=maildir:%$/%u/maildir, mailUidNumber=uid, mailGidNumber=gid, mailQuotaStorage=quota_rule=*:storage=%$, mailQuotaMessages=quota_rule2=*:messages=%$ pass_attrs = uid=user, userPassword=password, mailStorageDirectory=userdb_home=%$/%u, mailStorageDirectory=userdb_mail=maildir:%$/%u/maildir, mailUidNumber=userdb_uid, mailGidNumber=userdb_gid, mailQuotaStorage=userdb_quota_rule=*:storage=%$, mailQuotaMessages=userdb_quota_rule2=*:messages=%$ [...] Thanks

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