- dovecot - dovecot.org

Re: [Dovecot] Misbehavior with Dovecot and Mulberry
by Jon Roma 27 Sep '05

27 Sep '05

Sorry about that last -- Windows seems to have mangled the attachment. Retrying here.

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[Dovecot] stable 1.0 on FC3
by Obantec Support 27 Sep '05

27 Sep '05

Hi should this worry me dovecot: POP3(chelan): file mail-index-view-sync.c: line 60 (view_sync_get_expunges): assertion failed: (ret == 0) using mbox format under /var/spool/mail/ Mark -- Obantec Support www.obantec.net 0845 458 3121 WebHosting and Domains Nominet UK Member & IPStag Holder CentralNic Accredited Reseller

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[Dovecot] mail not found
by Michael Collins 27 Sep '05

27 Sep '05

This is in my dovecot.conf default_mail_env = maildir:/var/mail/vhosts/%1u/%u/ my mail ia in/var/mail/vhosts/anawebdesigns.com/user1/cur, new, tmp As you can guess these are virtual accounts. Auth works but mail is not found. How do I need to modify the line in dovecot.conf? Thanks. -- -- Michael H. Collins It's us against them. Ride like you stole it. If you love some code, set it free. Please avoid sending me Word or PowerPoint attachments. See http://www.gnu.org/philosophy/no-word-attachments.html

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Re: Re: Re: [Dovecot] virtual domain
by Barry Kwok 27 Sep '05

27 Sep '05

>On Tue, 2005-09-27 at 13:29 +0800, Barry Kwok wrote: >> userdb static { >> args = uid=503 gid=503 mail=mbox:/var/spool/virtual/%d/%n >> } > >Drop the "mail" part from here. You already have it in default_mail_env, >and it's correct there. Here you're saying that the .../%d/%n is the >mail directory, not file. If it refuses to start up without the mail= >part, replace it with home=/tmp instead. > >> Why I need a IMAP folder in a POP3 only server > >Dovecot is mostly an IMAP server, POP3 was just an afterthought. > >> and can I change that folder to /tmp directory. > >Yes, as long as nothing actually gets written there (and with >INDEX=MEMORY and POP3 nothing should get written there). > > Thank you Timo, I have just tried. But I found that I must add the mail=mbox:/var/spool/virtual/%d/%n part. Without this part, the dovecot seems not checking the right location of mail spool and simply say that "no new email". Now I added this part together with "home=/tmp" part into userdb config and It works now with IMAP folder in /tmp directory. But I want to ask if there is any file locking problem as I am running virtual email with vmail as owner for all mbox accounts. And it seems that they are all share the same IMAP folder located in /tmp directory.

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[Dovecot] Hostname passed to PAM as rhost
by Tom Alsberg 27 Sep '05

27 Sep '05

(I am sorry to bother the list with something I should have verified myself right now - I simply do not have access to the source code here) Thinking of some limit I wanted to put with authentication, I am wondering - when Dovecot authenticates a user using PAM, now that (in 1.0) it passes the rhost item to PAM, it passes a hostname, not an IP address. Does it double-verify the DNS record before it trusts this to be the hostname (first checking the IP address in in_addr.arpa and then checking that the hostname indeed maps back to the same IP address)? That is necessary in order to trust the client address when determining authentication strength in the PAM module based on the client location (specifically we want stronger authentication when the client comes outside of our network, while inside a plain password suffices), as else anybody could "spoof" the hostname by changing the IN PTR record of his IP address to point back to some "trusted" hostname (given he has control of the DNS zone his host is in, which is completely possible given the server knows nothing about it). Thanks, -- Tom -- Tom Alsberg - hacker (being the best description fitting this space) Web page: http://www.cs.huji.ac.il/~alsbergt/ DISCLAIMER: The above message does not even necessarily represent what my fingers have typed on the keyboard, save anything further.

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[Dovecot] POP3 problem
by michal 27 Sep '05

27 Sep '05

Hey all this is my first post to this list. I have fresh Red Hat AS 4.0 with postfix 2.1. This will be my mail server. I have one problem with pop3. My mail server is working properly. I did the following test: Sent an email to some other server(yahoo.com)->email got there fine. >From that other server(yahoo.com) replaied-> to the new server and email got there fine,checked using pine. Now in x windows on the mail server if i lunch email client software and set up the account, then i can send and receive emails fine so pop3 is working. But when i go to different machine like PC set up outlook then i cannot receive emails. I get error in outlook that the connection has failed. So i telnet 192.168.1.10 110 and I have gotten response from the server 250 dovecot OK. I really dont what to do at this time. I have been trying couple different things without any luck..... need some help? Mike

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[Dovecot] How safe is mbox_very_dirty_syncs?
by Chris Wakelin 27 Sep '05

27 Sep '05

I've tried turning on mbox_very_dirty_syncs for myself (and a few other brave souls running 1.0-alpha3 rather than 1.0-stable) again to see what perfomance gain it gives (see thread http://www.dovecot.org/list/dovecot/2005-July/007956.html) Now we aren't running UW-IMAP at all, how safe is mbox_very_dirty_syncs assuming the only other process writing to mailboxes is our MTA (exim) which simply appends messages to the end? Is it safer still using Dovecot 1.0-alphas and the LDA? Does it matter if there are concurrent connections to the mailbox? Best Wishes, Chris -- --+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+- Christopher Wakelin, c.d.wakelin(a)reading.ac.uk IT Services Centre, The University of Reading, Tel: +44 (0)118 378 8439 Whiteknights, Reading, RG6 2AF, UK Fax: +44 (0)118 975 3094

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[Dovecot] new mailbox format v2
by Timo Sirainen 27 Sep '05

27 Sep '05

Updated version. The previous one was a bit too complicated with flag updates for pretty minimal benefits. Changes: - writing/reading mail flags can be disabled to get better performance without it requiring any changes to how the files are normally handled (so mixed more works fine). - writing flags now requires getting shared locks. so there's the overhead of locking but flag writers don't have to wait for each others. - reading requires no locking anymore. the comment in the previous version about reading only half a mail being a problem doesn't actually matter, since if a client tries to read an expunged mail Dovecot already disconnects the client immediately (since most clients can't handle such situation well anyway). - no more problems with mailbox readers locking out expungers - note about fcntl() locking being able to provide even higher concurrency - works just fine with plain dotlocks, so works fine with NFS And looks like I forgot to explain the "mail header padding" before. I'm not exactly sure if it's useful or not, but it doesn't hurt to have it there if it's wanted. The idea was anyway that if you're writing more than one flag at a time, having a 512 byte padding would make sure that when writing the few bytes the OS will only have to read one sector from disk (512 bytes in all todays OSes I believe?) to get the non-written parts of the sector instead of possibly reading two sectors. So it might help with trading disk reads for some wasted disk space. Generic ------- The point is to have a mailbox format where the mailbox can consist of one or more files. Grouping multiple files in a single file makes it faster to read, but it's slower to expunge mails from the beginning of the file. So this format would allow sysadmin to specify rules on how large the files would be allowed to grow. Index File ---------- Named "index". Index file gives a mapping between UIDs <-> filenames: Header: <uidvalidity> <last-used-uid> Record: <uid-first> <uid-last> <filename> Record: .. eg.: 1127468129 5 1 3 msg.1 4 4 msg.4 All of the UIDs don't have to actually exist in the file if they have been expunged. The record should be removed once all of the UIDs have been removed from it (and the file itself been deleted). The same file may appear multiple times in the index. For example: 1 2 msg.1 3 3 msg.3 4 5 msg.1 This means that UIDs 1, 2, 4 and 5 are in file msg.1, but UID 3 is in file msg.3. The filename doesn't matter as long as it's unique, but probably wouldn't hurt to include its first UID in the filename so humans can find mails more easily. The filename however must not end with ".lock". The file is modified by creating first exclusively owned "index.lock" file, updating it and then rename()ing it over the index file. This lock file shouldn't be held for a long time, so if it exists, and it doesn't get modified at all within 30 seconds, it can be overwritten. Before rename()ing over the index file, you should check with stat() that the index.lock file is still the same as you expect it to be (in case your process was temporarily stopped for over 30 secs). The index file's mtime timestamp must grow after each modification. This makes it easy to check if new mail has been added to the mailbox. Mail File --------- File header: Bytes Format Description 8 hex Header size 16 hex Append offset 4 hex Mail header size 4 hex Mail header padding 4 hex Keyword count in mail headers Mail header: Bytes Format Description 8 hex UID 16 hex Mail size 1 1/0 Answered flag 1 1/0 Flagged flag 1 1/0 Deleted flag 1 1/0 Seen flag 1 1/0 Draft flag 1 1/0 Expunged flag n 1/0 Keywords The file layout then goes: <File header> - possible padding due to Header size <Mail header #1> - possible padding due to Mail header size <Mail data #1> - possible padding due to Mail header padding (ie. next Mail header's offset is divisible with Mail header padding) <Mail header #2> etc.. The UIDs must be ascending within the file (but as said above, some UIDs between them may exist in other files). If mail has been marked with expunged-flag, it should be treated as if it was already expunged. The mail will really be expunged later in some nightly run. Reading the files requires no locking. If while reading you happen to hit unexpected end of file, it means that mails were expunged from the file. After that you'll look at the index file again to see which file the mail went and continue from there on. If the mail isn't found, it means it got expunged. Expunging happens by locking the file and then copying all non-expunged mails after the first expunged one to new file. Then update the index file with the new location for the UIDs, and at last ftruncate() at the position of first expunged mail in the original file. Flag updates require locking the file as well, otherwise we might try to write past the end of file when another process is expunging the mails. Shared locking can be used for flag update locking since each flag update can be atomically changed by writing one byte. Appending mails can be done by either locking existing file and appending to it, or creating a new file. If appending to a new file, create it with .lock suffix and then check that the file without .lock wasn't already just created to prevent race conditions. When appending to existing file, check "Append offset" from file's header. If that offset is at the end of file, just append there. Otherwise read the mail's header from there. If it has a non-zero UID and index file says that the same UID exists in this file, jump over the mail and do the same checks for all the rest of the mails in the file. Once the check doesn't match or you reach EOF, update the append offset in the header to that offset and write your mail there. Initially write the UID in mail's header as zeroes ('0', not NUL). Once the append is completely finished, you'll have to update it with the new UID. You'll do this by locking index file, reading the latest last-used-uid and using the next value for your UID. Once you've written it, rewrite the index file with updated last-used-uid field and your UID added to it. After this, update the append offset in the mail file and unlock it. If fcntl() locking is used, locking only specific ranges can give more concurrency. Flag updates only need to lock the part of the file they're modifying. Expunges need to lock the part which it's removing. Appending needs to lock from <end of file-1> to end of file (ie. l_len=0). Keywords file ------------- Named "index.keywords". This contains mappings between keyword numbers and names. TODO: write how it's updated Recent file ----------- "index.recent.<uid>" file tells what the last non-recent UID was. The file doesn't have any data inside it. When opening the mailbox you should find and rename() the existing index.recent.<uid> file to the new index.recent.<last-uid>. A successful rename() means the mails between <uid>+1 .. <last-uid> are recent for you. A failed rename() means that someone else managed to do it. You should look for the file again and if it was renamed to less than <last-uid>, you should try again. Nightly cleanups ---------------- Because expunged mails may be left lying around for a while, there probably should be some nightly check that cleans them up. Other cleanups that may be necessary after crashes are: - .lock files - expunged data at the end of files (can be checked with same rules as how appending determines the offset where to append) Alternative ways to use ----------------------- Expunging mails isn't very filesystem quota friendly since it requires creating another file to copy the expunged mails to. This could also be done by just moving the data within the file. This however requires that all file reads must also be shared-locked. Also it has the problem of leaving the mailbox corrupted if the copying gets aborted in the middle. For the best performance the mail flags could be stored only in Dovecot's index files. In that case the flag update locking isn't slowing down expunges (and if fcntl() locks can't be used, doesn't slow down appends either). Also there's no need for keywords/recent files. Compatibility ------------- If needed, it would be possible to create new/ and tmp/ directories under the mailbox to allow mail deliveries to be in maildir format. The maildir files would be then either just moved or maybe be appended to existing mail files.

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[Dovecot] Mail directory funkiness
by Ted Kaczmarek 27 Sep '05

27 Sep '05

I am using dovecot-0.99.14-4.fc4 on FC4, was testing using mbox and than switched to using Maildir. default_mail_env = maildir:~/Maildir >From evolution when I create a folder the folder is created in ~/mail instead of ~/Maildir I am still rather new to dovecot, but this does not make sense. I made sure to restart dovecot, even added a .procmailrc. cat .procmailrc MAILDIR=/home/tedkaz/Maildir :0 ./ I am going to grab the latest version and test with that, but if if anyone has insight into how I got here it would be appreciated :-) Likely a pilot error. Regards, Ted

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Re: Re: [Dovecot] virtual domain
by Barry Kwok 27 Sep '05

27 Sep '05

>On Mon, 2005-09-26 at 21:33 +0800, Barry Kwok wrote: >> we are currently using vm-pop3d to implement virtual domains. But due to some locking problem in vm-pop3d, we want to test the possibility to change to dovecot. >> Currently, in vm-pop3d, the passwd file is located in >> /etc/virtual/domain1.com/passwd >> /etc/virtual/domain2.com/passwd > >passdb passwd-file { > args = /etc/virtual/%d/passwd >} > >This requires Dovecot 1.0.alpha2 or later. > >> and the passwd format is: >> user: md5 encrpted password > >In MD5crypt format? ie. $1$something? Then it should work directly. > >> and the email is store in >> /var/spool/virtual/domain1.com/user >> /var/spool/virtual/domain2.com/user > >As mboxes? For IMAP you'll need also some directory where non-INBOXes >are stored, and with POP3 Dovecot also wants a directory where it can >store index files. > >If you don't want either, you could do something like: > >default_mail_env = mbox:/tmp:INBOX=/var/spool/virtual/%d/%u:INDEX=MEMORY Thank you. Timo. I have installed Dovecot 1.0 alpha3 and tested. It is a mbox POP3 only server. The relevent part of dovecot.conf I have changed: default_mail_env = mbox:/tmp:INBOX:/var/spool/virutal/%d/%u:INDEX=MEMORY passdb passwd-file { # Path for passwd-file args = /etc/virtual/%d/passwd } userdb static { args = uid=503 gid=503 mail=mbox:/var/spool/virtual/%d/%n } I can login with user(a)domain1.com but there is error in logfile: Sep 27 13:15:16 ns2 dovecot: pop3(user(a)domain1.com): mbox: Can't create root IMAP folder /mail: Permission denied Sep 27 13:15:16 ns2 dovecot: pop3(user(a)domain1.com): Failed to create storage with data: mbox:/var/spool/virtual/domain1.com/user Sep 27 13:15:16 ns2 dovecot: pop3-login: Login: user=<user(a)domain1.com>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured Sep 27 13:15:16 ns2 dovecot: child 19147 (pop3) returned error 89 I then created a /mail directory with file mode 777, then it is OK. Why I need a IMAP folder in a POP3 only server and can I change that folder to /tmp directory.

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