I guess I've been lucky.  My Red Hat server I built in 2003 finally gave up the ghost yesterday.  Fifteen years with almost zero problems running 7x24.  Now I'm trying to build a basic server to host my e-mail using CentOS 7, Sendmail and Dovecot.   Server is running great as are Sendmail and Dovecot but Dovecot only allows connections from the CentOS 127.0.0.1.  I can telnet localhost pop3 and get a +OK Dovecot ready response.  Trying to telnet from a different computer on same LAN times out.  I've looked at my old Dovecot config files to see how I enabled LAN IP access but the configs have changed a lot since I last installed Dovecot.  Googling hasn't helped.  Anyone help with a sample config with LAN IPs permitted?