Can't receive E-mails after router swap

Today we replaced an old Instagate Ex with a new Sonicwall TZ-190  and we are having problems receiving E-mails.  We are currently running an exchange server on SBS 2003 and everything such as OWA or surfing the Internet works just fine.

When setting up the Sonicwall I used the Wizard to create a public server on port 25 that was supposed to move traffice from the WAN to the exchange server, however only sending is working.  I can telnet to the SMTP server inside the domain, just not through the Sonicwall.  When I try telnet through the sonicwall I get a flashing prompt and no error message.

Latest firmware has been pushed into the Sonicwall.  Any ideas anyone?
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Robbie_LeggettConnect With a Mentor Commented:
The rule on the Sonicwall has clearly been created incorrectly. Can you attach an image of the rule please? (Obviously blanking out the bits we're not meant to see) :-)
plythallAuthor Commented:
In the end, I found that the problem wasn't with the Sonicwall, but with the ISP providers in my area.  The network running the mail server is on an ADSL line provided by the local phone company, while I am using a cable internet based connection.  Apparently the phone company actually blocks telnet connections directory from one network to another.  Telnet worked just fine once I connected to a system on an ADSL line by the same phone company.
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