I installed FC4 as a mail server. Then I used Outlook to test it. The POP3 (incoming email) was passed, however, the outgoing (SMTP, port 25) failed. I got the error message: The TCP/IP connection was unexpectedly terminated by the server.(server: '192.168.2.214', Error Number 0x800ccc0f). I checked the server using nmap localhost, I got the following output: Starting nmap 3.81 ( http://www.insecure.org/nmap/ ) at 2006-03-30 16:36 EST Interesting ports on mail1.avensys.ca (127.0.0.1): (The 1652 ports scanned but not shown below are in state: closed) PORT STATE SERVICE 21/tcp open ftp 22/tcp open ssh 25/tcp open smtp 80/tcp open http 110/tcp open pop3 111/tcp open rpcbind 143/tcp open imap 443/tcp open https 993/tcp open imaps 995/tcp open pop3s 3306/tcp open mysql It seems that smtp port 25 is open. I also use netstat -tap to get the following result: Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 *:imaps *:* LISTEN 1767/xinetd tcp 0 0 *op3s *:* LISTEN 1767/xinetd tcp 0 0 *:mysql *:* LISTEN 1870/mysqld tcp 0 0 *op3 *:* LISTEN 1767/xinetd tcp 0 0 *:imap *:* LISTEN 1767/xinetd tcp 0 0 *:sunrpc *:* LISTEN 1554/portmap tcp 0 0 *:ftp *:* LISTEN 1946/proftpd: (acce tcp 0 0 192.168.2.214:5335 *:* LISTEN 1720/mDNSResponder tcp 0 0 192.168.2.214:smtp *:* LISTEN 1937/master tcp 0 0 *:http *:* LISTEN 1962/httpd tcp 0 0 *:ssh *:* LISTEN 1759/sshd tcp 0 0 *:https *:* LISTEN 1962/httpd tcp 0 144 ::ffff:192.168.2.214:ssh ::ffff:192.168.2.40:4817 ESTABLISHED 2647/0 I saw smtp was listening. What's wrong with me? Any suggestion? Thanks a lot.