Two users reported that they were not receiving any email this morning. I logged into the email server, which is a CentOS Linux system using Dovecot to provide POP3 email service, i.e., it is the software on the server to which email clients connect to download users' email. I then connected to the POP3 port, TCP port 110, using the Telnet program on the system and attempted to check email for a user's account by issuing the
user command, but after I entered the command
the connection was terminated before I could enter the pass
command with the password for the account.# telnet 127.0.0.1 110 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. user nell Connection closed by foreign host. #
So I then checked Dovecot's log file. I saw many entries similar to the following ones in that file:
# grep dovecot /var/log/maillog | tail -5 Jul 4 09:15:44 moonpoint dovecot: master: Warning: service(pop3-login): process _limit (100) reached, client connections are being dropped Jul 4 09:18:55 moonpoint dovecot: master: Warning: service(pop3-login): process _limit (100) reached, client connections are being dropped Jul 4 09:19:57 moonpoint dovecot: master: Warning: service(pop3-login): process _limit (100) reached, client connections are being dropped Jul 4 09:21:01 moonpoint dovecot: master: Warning: service(pop3-login): process _limit (100) reached, client connections are being dropped Jul 4 09:26:13 moonpoint dovecot: master: Warning: service(pop3-login): process _limit (100) reached, client connections are being dropped #
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