Hi all,
I have recently started to use CentOS. I have setup a mail server running centos 4.3 with dovecot, sendmail, and spamassassin. The user information is located in a openlapd database on a separate machine.
I am currently seeing connection from the mail server to the ldap server left open which causes some interesting behavior. Sendmail will occasionally return email messages as user unknown when the user exists. This behavior will steadily get worse until the number of connections fill up. When ldap is restarted the process starts over again. If ldap is restarted every hour the behavior stated above is not seen. Email is delivered as would be expected.
Doing tcpdump shows connections from dovecot and sendmail that have are in an open state. I find the connections that were is the open state finish their request and close. Occasionally I see connections that were doing dovecot authentication before the reset will change and do a sendmail request then close.
When a load was first put to the mail server dovecot authentication would just start (authenticate < 10 people) and lockup. Upon googling I found a article that said to set dovecot to use ldap directly instead of using pam (create the dovecot-ldap.conf file). This I did and the authentication problem appeared to have gone away.
I have tried to find information to help solve this problem of the open connection but without success.
If someone could point me in the right direction to solve this problem it would be appreciated.
Myron Williams