Re: Help regarding Postfix and Dovecot SASL

19 Jan 2026


      Drop user=dovecot from service lmtp.
Aki
...
On 19/01/2026 14:35 EET Christophe Lohr via dovecot <dovecot@dovecot.org> wrote:
Le 19/01/2026 à 10:58, Aki Tuomi via dovecot a écrit :
...
you can try
log_debug=category=lmtp
Many thanks!
Thereisclearlysomeconfusionsomewherebetweenthevmailuserandthedovecotuser(nottomentionthatanvilisundertherootuser):
Jan 19 13:13:56 lmtp(4940): Error: conn unix:/run/dovecot/anvil:
net_connect_unix(/run/dovecot/anvil) failed: Permission denied
Jan 19 13:13:56
lmtp(alice7@my_domain.org)<4940><g39gDwQgbmlMEwAAfWgqOQ>: Fatal:
setresgid(2222(vmail),2222(vmail),8(mail)) failed with
euid=118(dovecot): Operation not permitted
Jan 19 13:13:56 lmtp: Fatal: master: service(lmtp): child 4940 returned
error 89 (Fatal failure)
How can I fix this?
Best regards
Christophe
PS:  Here is my current doveconf:
2.4.1-4 (7d8c0e5759): /etc/dovecot/dovecot.conf
Pigeonhole version 2.4.1-4 (0a86619f)
OS: Linux 6.12.63+deb13-amd64 x86_64 Debian 13.3
Hostname: pc-serveur
4 default setting changes since version 2.4.0
dovecot_config_version = 2.4.0
auth_allow_cleartext = yes
auth_debug = yes
auth_debug_passwords = yes
auth_mechanisms = plain
auth_verbose = yes
auth_verbose_passwords = yes
default_login_user = vmail
dovecot_storage_version = 2.4.0
first_valid_gid = 2222
first_valid_uid = 2222
fts_autoindex = yes
fts_autoindex_max_recent_msgs = 999
fts_search_add_missing = yes
info_log_path = /var/log/dovecot-info.log
log_debug = category=lmtp
log_path = /var/log/dovecot.log
mail_access_groups = vmail
mail_driver = maildir
mail_home = /var/spool/vmail/%{user|lower}
mail_inbox_path = /var/spool/vmail/%{user|lower}/Maildir
mail_path = ~/Maildir
mail_privileged_group = mail
protocols = imap lmtp
ssl = no
verbose_proctitle = yes
namespace inbox {
inbox = yes
mailbox Drafts {
special_use = "\\Drafts"
}
mailbox Junk {
special_use = "\\Junk"
}
mailbox Trash {
special_use = "\\Trash"
}
mailbox Sent {
special_use = "\\Sent"
}
mailbox "Sent Messages" {
special_use = "\\Sent"
}
}
service imap-login {
process_min_avail = 1
user = vmail
inet_listener imap {
port = 143
listen = 192.168.100.1 127.0.0.1 [::1]
}
inet_listener imaps {
}
}
service pop3-login {
inet_listener pop3 {
}
inet_listener pop3s {
}
}
service submission-login {
inet_listener submission {
}
inet_listener submissions {
}
}
service lmtp {
executable = lmtp -L
user = dovecot
unix_listener lmtp {
}
unix_listener /var/spool/postfix/private/dovecot-lmtp {
group = postfix
mode = 0600
user = postfix
}
}
service imap {
}
service pop3 {
}
service submission {
}
service auth {
user = dovecot
unix_listener auth-userdb {
}
unix_listener auth-chasquid-userdb {
mode = 0660
user = chasquid
}
unix_listener auth-chasquid-client {
mode = 0660
user = chasquid
}
unix_listener /var/spool/postfix/private/auth {
group = postfix
mode = 0660
user = postfix
}
}
service auth-worker {
user = dovecot
}
service dict {
unix_listener dict {
}
}
ssl_server {
cert_file = /etc/dovecot/private/dovecot.pem
key_file = /etc/dovecot/private/dovecot.key
}
protocol lmtp {
auth_username_format = %{user|lower}
info_log_path = /var/log/dovecot-lmtp.log
}
passdb passwd-file {
passwd_file_path = /etc/dovecot/passwd
}
userdb passwd-file {
passwd_file_path = /etc/dovecot/passwd
fields {
gid = vmail
home = /var/spool/vmail/%{user|lower}
uid = vmail
}
}
Le 19/01/2026 `a 10:58, Aki Tuomi via dovecot a ecrit :
you can try
log_debug=category=lmtp
Many thanks!
There  is  clearly  some  confusion  somewhere  between  the  vmail  user
and  the  dovecot  user (not  to  mention  that  anvil  is  under  the
root  user):
Jan 19 13:13:56 lmtp(4940): Error: conn unix:/run/dovecot/anvil:
net_connect_unix(/run/dovecot/anvil) failed: Permission denied
Jan 19 13:13:56
lmtp([1]alice7@my_domain.org)<4940><g39gDwQgbmlMEwAAfWgqOQ>: Fatal:
setresgid(2222(vmail),2222(vmail),8(mail)) failed with euid=118(dovecot):
Operation not permitted
Jan 19 13:13:56 lmtp: Fatal: master: service(lmtp): child 4940 returned
error 89 (Fatal failure)
How can I fix this?
Best regards
Christophe
PS:  Here is my current doveconf:
2.4.1-4 (7d8c0e5759): /etc/dovecot/dovecot.conf
Pigeonhole version 2.4.1-4 (0a86619f)
OS: Linux 6.12.63+deb13-amd64 x86_64 Debian 13.3
Hostname: pc-serveur
4 default setting changes since version 2.4.0
dovecot_config_version = 2.4.0
auth_allow_cleartext = yes
auth_debug = yes
auth_debug_passwords = yes
auth_mechanisms = plain
auth_verbose = yes
auth_verbose_passwords = yes
default_login_user = vmail
dovecot_storage_version = 2.4.0
first_valid_gid = 2222
first_valid_uid = 2222
fts_autoindex = yes
fts_autoindex_max_recent_msgs = 999
fts_search_add_missing = yes
info_log_path = /var/log/dovecot-info.log
log_debug = category=lmtp
log_path = /var/log/dovecot.log
mail_access_groups = vmail
mail_driver = maildir
mail_home = /var/spool/vmail/%{user|lower}
mail_inbox_path = /var/spool/vmail/%{user|lower}/Maildir
mail_path = ~/Maildir
mail_privileged_group = mail
protocols = imap lmtp
ssl = no
verbose_proctitle = yes
namespace inbox {
inbox = yes
mailbox Drafts {
special_use = "\\Drafts"
}
mailbox Junk {
special_use = "\\Junk"
}
mailbox Trash {
special_use = "\\Trash"
}
mailbox Sent {
special_use = "\\Sent"
}
mailbox "Sent Messages" {
special_use = "\\Sent"
}
}
service imap-login {
process_min_avail = 1
user = vmail
inet_listener imap {
port = 143
listen = 192.168.100.1 127.0.0.1 [::1]
}
inet_listener imaps {
}
}
service pop3-login {
inet_listener pop3 {
}
inet_listener pop3s {
}
}
service submission-login {
inet_listener submission {
}
inet_listener submissions {
}
}
service lmtp {
executable = lmtp -L
user = dovecot
unix_listener lmtp {
}
unix_listener /var/spool/postfix/private/dovecot-lmtp {
group = postfix
mode = 0600
user = postfix
}
}
service imap {
}
service pop3 {
}
service submission {
}
service auth {
user = dovecot
unix_listener auth-userdb {
}
unix_listener auth-chasquid-userdb {
mode = 0660
user = chasquid
}
unix_listener auth-chasquid-client {
mode = 0660
user = chasquid
}
unix_listener /var/spool/postfix/private/auth {
group = postfix
mode = 0660
user = postfix
}
}
service auth-worker {
user = dovecot
}
service dict {
unix_listener dict {
}
}
ssl_server {
cert_file = /etc/dovecot/private/dovecot.pem
key_file = /etc/dovecot/private/dovecot.key
}
protocol lmtp {
auth_username_format = %{user|lower}
info_log_path = /var/log/dovecot-lmtp.log
}
passdb passwd-file {
passwd_file_path = /etc/dovecot/passwd
}
userdb passwd-file {
passwd_file_path = /etc/dovecot/passwd
fields {
gid = vmail
home = /var/spool/vmail/%{user|lower}
uid = vmail
}
}
References
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