I upgraded my Linux kernel and dovecot failed to start with the following error messages:
Error: service(managesieve-login): listen(*, 4190) failed: Address already in use
Error: service(pop3-login): listen(*, 110) failed: Address already in use
Error: service(pop3-login): listen(*, 995) failed: Address already in use
Error: service(imap-login): listen(*, 143) failed: Address already in use
Error: service(imap-login): listen(*, 993) failed: Address already in use
Fatal: Failed to start listeners
Strangely enough, I couldn't find any process bounded to those port numbers. All commands below return nothing.
# netstat -tulpn | grep 110
# ss -tulpn |grep 110
# fuser 110/tcp
# lsof -i :110
I also tried to change the listen setting to my specific IP address and it still failed the same way.
Any idea how I can solve this problem? Here's my version info:
# uname -a
Linux ip-172-31-26-222 4.14.177-107.254.amzn1.x86_64 #1 SMP Thu May 7 18:30:14 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
# dovecot --version
2.2.36 (1f10bfa63)
Hi it looks like you are using AWS as I am. I recently updated via Yum as well. I noticed that a new package named 'portreserve' was also installed. I killed that process, left the /etc/dovecot/dovecot.conf as it was before and then started Dovecot successfully. I was also immediately able to reconnect my mail clients connection. I hope that helps you.
I also restarted the portreserve program since it seems useful to limit port access.