Sendmail not accepting connections on port 25

[ssgriffonuser]

Hi all,

I'm having difficulty getting sendmail set up on my server.  I can send 
and receive to localhost and I can send to external networks but I can 
not receive from external networks (I receive a 550: Address rejected).  
Netstat says sendmail is listening on port 25 but I cannot telnet to it.
When I do a port scan of the server, nmap does not show anything on port 
25 but does show smtp on 587.

As far as configuration goes, I added my hostname to 
/etc/mail/local-host-names and created a /etc/host/virtusertable that 
looks like:

admin at host.com    shane
shane at host.com    shane

then I ran 'make all install restart' .

A couple more things that might be useful, I have a second ethernet 
interface that I am guessing my provider uses for maintenance (internal 
lan) and I shut my firewall completely off while testing.

The output of netstat and (filtered) nmap is:

netstat -a | grep smtp*:

*tcp6**0    0    0 *.smtp     *.*    LISTEN
tcp4**0    0    0 *.smtp     *.*    LISTEN

nmap -A -T4 gatanova.com  Starting Nmap 5.51 ( http://nmap.org ) at 
2011-07-18 22:27 MST
Not shown: 996 filtered ports PORT     STATE SERVICE VERSION
587/tcp  open  smtp    Sendmail 8.14.4/8.14.4
| smtp-commands: gatanova Hello ip24-251-146-122.ph.ph.cox.net 
[24.251.146.122], pleased to meet you, ENHANCEDSTATUSCODES, PIPELINING, 
8BITMIME, SIZE, DSN, DELIVERBY, HELP
|_ 2.0.0 This is sendmail version 8.14.4 2.0.0 Topics: 2.0.0 HELO EHLO 
MAIL RCPT DATA 2.0.0 RSET NOOP QUIT HELP VRFY 2.0.0 EXPN VERB ETRN DSN 
AUTH 2.0.0 STARTTLS 2.0.0 For more info use "HELP <topic>". 2.0.0 To 
report bugs in the implementation see 2.0.0 
http://www.sendmail.org/email-addresses.html 2.0.0 For local information 
send email to Postmaster at your site. 2.0.0 End of HELP info

Any help is greatly appreciated!