postfix errors fatal: no SASL authentication mechanisms /usr/libexec/postfix/smtpd: bad command startup -- throttling solution

Jul  3 22:12:17mailserver postfix/smtpd[6195]: fatal: no SASL authentication mechanisms
Jul  3 22:12:18mailserver postfix/master[4881]: warning: process /usr/libexec/postfix/smtpd pid 6195 exit status 1
Jul  3 22:12:18mailserver postfix/master[4881]: warning: /usr/libexec/postfix/smtpd: bad command startup -- throttling

This only ever happens in my experience when the authentication method is actually Dovecot.  Usually the problem will be that Dovecot cannot start due to a misconfiguration and or permissions issue. 

The solution is to try to trace through /var/log/maillog and find out what is wrong with Dovecot (assuming it cannot start).

After this postfix should work fine.

You should also enable debug info in dovecot.conf like this:

auth_debug = yes
auth_debug_passwords = yes
auth_verbose = yes

To give you an idea of what commonly goes wrong after a new Dovecot migration or install:

dovecot: auth: Error: passwd-file /etc/dovecot.passwd: open(/etc/dovecot.passwd) failed: Permission denied (euid=97(dovecot) egid=97(dovecot) missing +r perm: /etc/dovecot.passwd, euid is not dir owner)

Solution:

chmod +x /etc/dovecot.passwd

Another error:

dovecot: lda: Error: userdb lookup: connect(/var/run/dovecot/auth-userdb) failed: Connection refused

In this case you need to make sure /var/run/dovecot/auth-userdb and also /var/mail is set to the correct user id and group id or username/groupname as in your /etc/dovecot/dovecot.conf

first_valid_gid = 502
first_valid_uid = 501
last_valid_gid = 502
last_valid_uid = 501

 


Tags:

postfix, errors, fatal, sasl, authentication, mechanisms, usr, libexec, smtpd, startup, throttling, solutionjul, mailserver, jul, pid, method, dovecot, misconfiguration, permissions, var, maillog, enable, debug, info, conf, auth_debug, auth_debug_passwords, auth_verbose, commonly, migration, install, auth, passwd, etc, euid, egid, perm, dir, chmod, lda, userdb, lookup, user, username, groupname, first_valid_gid, first_valid_uid, last_valid_gid, last_valid_uid,

Latest Articles

  • ssh Too many authentication failures not prompting for password
  • LightDM Mint Ubuntu Debian won't start errors Nvidia Graphics
  • WARNING: Unable to determine the path to install the libglvnd EGL vendor library config files. Check that you have pkg-config and the libglvnd development libraries installed, or specify a path with --glvnd-egl-config-path. Linux Ubuntu Mint Debian E
  • How To Upgrade Linux Mint 18.2 to 18.3 to 19.x and 20.x
  • MP3s Won't Play / ID3 Version 2.4 Issues in Cars and Other MP3 Players/CDs/DVDs Solution
  • LXC Containers LXD How to Install and Configure Tutorial Ubuntu Debian Mint
  • GlusterFS HowTo Tutorial For Distributed Storage in Docker, Kubernetes, LXC, KVM, Proxmox
  • Ubuntu Mint audio output not working pulseaudio "pulseaudio[13710]: [pulseaudio] sink-input.c: Failed to create sink input: too many inputs per sink."
  • How To Shrink Dynamically Allocated VM QEMU KVM VMware Disk Image File
  • How To Enable Linux Swapfile Instead of Partition Ubuntu Mint Debian Centos
  • 404 Not Found [IP: 151.101.194.132 80] apt update Debian 11 Bullseye Solution The repository 'http://security.debian.org bullseye/updates Release' does not have a Release file.
  • WARNING: Can't download daily.cvd from db.local.clamav.net freshclam clamav error solution
  • (firefox:9562): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Failed to execute child process "dbus-launch" (No such file or directory) Solution
  • Debian Mint Ubuntu Which Package Provides missing top, ps and w Solution
  • Vbox Virtualbox DNS NAT Network Mode NOT working
  • Docker Tutorial HowTo Install Docker, Use and Create Docker Container Images Clustering Swarm Mode Monitoring Service Hosting Provider
  • Zoom Password Error 'That passcode was incorrect' - Solution Wrong Passcode Wrong Meeting Name
  • How To Startup and Open Remote/Local Folder/Directory in Ubuntu Linux Mint automatically upon login
  • How To Reset Windows Server Password 2019, 2022, 7, 8, 10, 11 Recovery and Removal Guide Using Linux Ubuntu Mint Debian
  • How To Create OpenVPN Server for Secure Remote Corporate Access in Linux Debian/Mint/Ubuntu with client public key authentication