Sendmail cannot send outgoing email locally

[chupmunk]

A newly installed Linux (FC6) Server, planning to be a internal email server, no RELAY, just local uses email communicate to local users

Dovecot, Sendmail both installed and start, WITHOUT 'DNS'
Servername (default) : localhost.localdomain

**Testing 1**

Under Fc6 Kernal test the following:

telnet localhost 25 [within 1 seconds, OK]
telnet localhost 110 [within 1 seconds, OK]
telnet 192.168.0.x 25 [within 1 seconds, OK]
telnet 192.168.0.x 110 [wait 60-75 seconds, finally ok] <-- This is the problem

The problem is why? using IP address will cause a time delay?

**Testing 2**

Under Outlook Express

Receiving Email [fast, OK]
Sending Email [wait 60-75 seconds, sometime ok, somtime not]

So, the question should be back from why telnet under FC6 kernal have problem first?

log from \var\log\maillog
-------------------------------------------------------------------------------------------------
Jul 13 15:02:40 localhost sm-msp-queue[1998]: restarting /usr/sbin/sendmail due to signal
Jul 13 15:02:40 localhost sendmail[1990]: restarting /usr/sbin/sendmail due to signal
Jul 13 15:02:40 localhost sm-msp-queue[28969]: starting daemon (8.13.8): queueing@01:00:00
Jul 13 15:02:40 localhost sendmail[28971]: starting daemon (8.13.8): SMTP+queueing@01:00:00
---------------------------------------------------------------------------------------------------

Anyone know is it related to the last line of log "SMTP+queueing@01:00:00", what is it?