September 2023 - dovecot

JMAP support?
by Mark Constable 31 Jan '24

31 Jan '24

On Fri Jan 25 2019 Aki wrote: > There is no JMAP support in any dovecot version yet. Two years on so what is the status of JMAP support in Dovecot now?

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Replication going away?
by Vladimir Mishonov 26 Jan '24

26 Jan '24

Hello everyone. Just saw this commit in the official Github repo: https://github.com/dovecot/core/commit/4c04e4c30fd4817a8b0e11d04d9681173f69… Looking at the commit details, it appears that it completely removes the replication feature. I'm a bit perplexed by this change and am not sure what might be the justification for it. Personally, I find replication to be very useful, as it allows me to maintain a synchronized mirror of all of my mailboxes on my home server, for use as backup in case the primary server goes down for some reason. Perhaps there's some sort of replacement being planned for this feature? Or maybe the relevant code is simply going to be refactored to a plugin or external program, and there's nothing to worry about at all? In any case, I'd greatly appreciate if one of the developers could comment on this change. -- Kind regards, a concerned user of Dovecot (Vladimir)

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Forcing imap authentication failure for certain IP addresses
by Hippo Man 20 Jan '24

20 Jan '24

I'm running dovecot 2.3.18 under Debian 11. I want to do something that's a bit unusual: when IMAP connections are attempted from a few specific IP addresses, I want to force an IMAP authentication failure from those connections, no matter what user ID and password are specified. I know that I can use iptables to completely block imap access from those IP addresses to the IMAP ports. However, in these specific cases, I'd prefer that the connection goes through to dovecot, but for dovecot then to always generate authentication failures for those specific connections ... even if a valid user ID and password happen to be specified. Is there a way to do this in dovecot? Thank you very much in advance. -- hippoman(a)gmail.com Take a hippopotamus to lunch today. .---------, 0__0 / ( oo'---, / oo\ ,\ | | \ ,=__/ \ / / /------| /| |__|-' |__|'

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replicator: Panic: data stack: Out of memory when allocating 268435496 bytes
by Gerben Wierda 06 Dec '23

06 Dec '23

One step further in my quest to create a replacement mail server. I now have my old mail server (2.3.19.1, macOS + MacPorts) and my new (2.3.20, Alpine Linux, Docker, apk package). When I turn on replication it works, but, after a while I see: Jan 06 00:50:31 replicator: Panic: data stack: Out of memory when allocating 268435496 bytes Jan 06 00:50:32 replicator: Fatal: master: service(replicator): child 133 killed with signal 6 (core dumped) Jan 06 00:50:32 lmtp(pid 195 user sysbh): Warning: replication(sysbh): Sync failure: Jan 06 00:50:32 lmtp(pid 195 user sysbh): Warning: replication(sysbh): Remote sent invalid input: - I've removed synchronous operation for now (found a message on the net suggesting that) but is this known and what does it mean? Gerben Wierda (LinkedIn <https://www.linkedin.com/in/gerbenwierda>) R&A IT Strategy <https://ea.rna.nl/> (main site) Book: Chess and the Art of Enterprise Architecture <https://ea.rna.nl/the-book/> Book: Mastering ArchiMate <https://ea.rna.nl/the-book-edition-iii/>

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Can Dovecot Use Wildcard TLS Certificates?
by duluxoz 07 Nov '23

07 Nov '23

Hi All, Quick Q: Can dovecot use wildcard TLS Certificates? I'm having issues with a new dovecot/postfix stack set-up and I can't get mutt on the local box to connect via imap - its coming back with an SSL error, and as I'm using a wildcard cert for the domain I was wondering if that was my issue. If dovecot can use wildcard certs then I'll look elsewhere in my troubleshooting. Thanks in advance Cheers Dulux-Oz

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{ldap:objectGUID} returns binary data when used for user_attrs
by Andreas Haerter 26 Oct '23

26 Oct '23

Hi, there is an environment in which I have to use MS Active Directory for authentication and mail server user database, and I've run into a problem. I. The problem I want to retrieve the objectGUID attribute for the homedir path of the users. This attribute does never change, even when the username does or the account gets moved to another AD domain. However, the objectGUID is returned as binary gibberish when using the following setting: > user_attrs = \ > =home=/var/vmail/example.com/%LT{ldap:objectGUID}, \ It results in > # doveadm user uTesting > field value > user utesting > home /var/vmail/example.com/d ��n�aa_ o�� > mail maildir:~/mail Can someone reproduce this or offer a workaround? The only idea I had was hashing the value using =%M{ldap:objectGUID}. However, this approach would become problematic if the behavior changes and a proper string representation is returned, as expected, instead of the binary data. Therefore, I'm hesitant to use this method for now. A better approach would be encoding it as Base64, but I was unsuccessful to identify a fitting modifier at <https://doc.dovecot.org/configuration_manual/config_file/config_variables/#…>. Any ideas? II. Additional info Using other attributes for LDAP/Active Directory works as expected. E.g. > =home=/var/vmail/example.com/%LT{ldap:sAMAccountName} results in > # doveadm user uTesting > field value > user utesting > home /var/vmail/example.com/utesting > mail maildir:~/mail The objectGUID is indeed binary data, but IHMO, it should be handled differently when returned. E.g. there is a defined string representation, [MS-DTYP] section 2.3.4.3: <https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dtyp/222af…> which links to: > curly braced GUID string: The string representation of a 128-bit > globally unique identifier (GUID) using the form > {XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}, where X denotes a hexadecimal > digit. The string representation between the enclosing braces is the > standard representation of a GUID as described in [RFC4122] section 3. > Unlike a GUIDString, a curly braced GUID string includes enclosing braces. Some libs simply decide to return the data Base64 encoded (which would be OK, too). E.g. openldap-clients / ldapsearch does so with objectGUID and objectSid: > $ ldapsearch [...] > [...] > # uTesting, common, user, managed, example.com > dn: CN=uTesting,OU=common,OU=user,OU=managed,DC=example,DC=com > [...] > name: uTesting > objectGUID:: RCDirQPvGU6KQUFfIE/i2Q== > [...] > objectSid:: AQUAAAAAAAUVAAAALenCqsullBUfFoubWQQAAA== > [...] > sAMAccountName: uTesting > [...] Other software had comparable bugs or behavior , e.g. sssd ("Properly handle AD's binary objectGUID"): <https://bugzilla.redhat.com/show_bug.cgi?id=1205382> <https://github.com/SSSD/sssd/issues/3629> owncloud ("ensure that objectguid or guid really return binary data before converting it"): <https://github.com/owncloud/core/issues/8317> III. Software versions, config I can reproduce the issue on Fedora Server 38 > # cat /etc/redhat-release > Fedora release 38 (Thirty Eight) > # uname -r > 6.4.15-200.fc38.x86_64 > # dovecot --version > 2.3.20 (80a5ac675d) and CentOS 9 Stream: > # cat /etc/redhat-release > CentOS Stream release 9 > # uname -r > 5.14.0-364.el9.x86_64 > # dovecot --version > 2.3.16 (7e2e900c1a) I did not try a Debian-based distro yet. The config itself works fine, relevant settings just for reference (as there are not many examples on the internet, maybe useful for somebody): > auth_username_format = %Lu > > passdb { > driver = ldap > args = /etc/dovecot/dovecot-ldap.conf.ext > } > userdb { > driver = ldap > args = /etc/dovecot/dovecot-ldap-userdb.conf.ext > } with the following options to exclude inactive accounts, search smtp proxy addresses and having a mandatory group membership in SERVICE_EmailUsers: > base = OU=common,OU=user,OU=managed,DC=example,DC=com > scope = subtree > > user_filter = \ > (& \ > (objectClass=user) \ > (objectCategory=Person) \ > (|(sAMAccountName=%{username})(mail=%{username})(proxyAddresses=smtp:%{username}@%{domain})) \ > (!(userAccountControl:1.2.840.113556.1.4.803:=2)) \ > (memberOf:1.2.840.113556.1.4.1941:=SERVICE_EmailUsers) \ > ) > pass_filter = \ > (& \ > (objectClass=user) \ > (objectCategory=Person) \ > (|(sAMAccountName=%{username})(mail=%{username})(proxyAddresses=smtp:%{username}@%{domain})) \ > (!(userAccountControl:1.2.840.113556.1.4.803:=2)) \ > (memberOf:1.2.840.113556.1.4.1941:=SERVICE_EmailUsers) \ > ) I will blog about the config in more detail at https://foundata.com/en/blog/ soon, especially when the objectGUID is solved (maybe hashing it really the way to go). :-) Regards, Andreas -- foundata GmbH Steinhäuserstr. 20 76135 Karlsruhe Sitz der Gesellschaft: Karlsruhe Registergericht: Amtsgericht Mannheim, HRB 714807 Geschäftsführer: Andreas Haerter USt-IdNr.: DE284122682

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Debian package for bookworm
by Claudio Corvino 14 Oct '23

14 Oct '23

Hi guys, I updated to Debian 12 but I can't find repo for bookworm on https://repo.dovecot.org/. When it will be released? Thanks! -- Claudio

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bug report: lmtp fails on root-squashed NFS filesystem
by Anne Bennett 09 Oct '23

09 Oct '23

Hi, all. I'm trying to set up Postfix with dovecot LTMP delivery on a host where the user files (/var/spool/mail as well as home directories) are on NFS filesystems, which are exported root-squashed to the mail server. I definitely don't want to give the mail server root permissions on the user files. LMTP delivery fails with this logged message (e.g.): Nov 16 17:51:36 lust dovecot: lmtp(anne)<16830><mkkzEPg1lGG+QQAAs/mAJw>: msgid=<202111162229.1AGMTfAO024765(a)vindemiatrix.encs.concordia.ca>: save failed to INBOX: Read-only mbox I found this posting where someone else had a similar problem and traced it in some detail back in 2019: https://dovecot.org/list/dovecot/2019-February/114611.html but apparently no one answered the fellow. In order to check that this is indeed the same problem, I temporarily changed the INBOX definition to make it write into /var/tmp/ (on a local filesystem), and delivery worked. I then temporarily changed the INBOX definition to make it write into an NFS filesystem with root NOT squashed, and again it worked (after I chmodded the directory to 1777 to allow any user to create a file). I believe that the person who wrote the above posting is correct: at some point, file access is (incorrectly) checked as root instead of as the target user. This is a bit of a showstopper for me. Any plans to address this? I attach the output of "dovecot -n", fwiw, but I don't think that this is a configuration problem... Anne. -- Ms. Anne Bennett, Senior Sysadmin, ENCS, Concordia University, Montreal H3G 1M8 anne(a)encs.concordia.ca +1 514 848-2424 x2285

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Compression: all or nothing?
by Alex King 03 Oct '23

03 Oct '23

Using 2.3.13 (89f716dc2) (debian package), with mdbox storage. I considering adding the zlib plugin. I understand that reading mail can cope with either compressed or uncompressed mailboxes. I'm wondering if I can leave the main storage uncompressed, while having the alternate storage compressed. There does not seem to be a way to configure this, from https://doc.dovecot.org/settings/plugin/zlib-plugin/ it seems compression (on saving emails) is an all-or-nothing option? Can I leave zlib_save unset in my main configuration, and have doveadm use some alternate configuration with zlib_save set? It doesn't look hopeful because I don't see the ability to use a different config at https://wiki.dovecot.org/Tools/Doveadm/Altmove. Perhaps I would need multiple copies of the daemon running? Or is it better just to compress everything? I plan to store older mails (perhaps 3months+) in the alternative storage, and was thinking it would be nice to have those compressed, while I don't need to compress the main store. Any feedback welcome. Thanks, Alex

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Separators and shared namespaces
by Francis Augusto Medeiros-Logeay 28 Sep '23

28 Sep '23

Hi Martin, I had a similar problem: https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thread/DNHM3… It seemed to me that using ‘.’ truncated the domain name when that was used in the paths, such as when using %d. Best, Francis

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