Randy,
Here's the ouput from mail "-i -v":

OpenSocket(25,194.6.110.10,$000000C0,0)
220 easyjet3.easyjet.co.uk Server SMTP (Complaints/bugs to: Postmaster)
>>> EHLO c3po.easyjet.com
500 Unknown or unimplemented command
>>> RSET
250 OK
>>> HELO c3po.easyjet.com
250 easyjet3.easyjet.co.uk - you are a charlatan
>>> MAIL FROM:<[log in to unmask]>
RecvSocket: IPCRECV: SOCKET TIMEOUT.  (SOCKERR 59)
Program terminated in an error state. (CIERR 976)

When I telnet from the HP3000 to port 25 and type
HELO  HELP  HELP ^J^M or HELP ^M^J then there is no response
HELP ^J^M^J^M gives the response 500 Unknown or unimplemented command
HELP ^M^J^M   gives the response 500 Unknown or unimplemented command

When I telnet from my SCO box to port 25 (on the SCO box)
typing ^J o ^M on their own elicits the response 500 Unknown or
unimplemented command
HELP followed by ^J or ^M gives the response:
214-The following commands are accepted:
214-helo noop mail data rcpt help quit rset expn vrfy
214-
214 Send complaints/bugs to:  Postmaster

Does that help in any way? I am not sure about DNS things but this problem
looks more fundamental than that doesn't it? BTW we are running SCO OSR5 -
it's been in about 2 years.

Thanks again
Clive
----------
> From: [log in to unmask]
> To: [log in to unmask]
> Subject: Re: [HP3000-L] Problems with email from telamon
> Date: 02 December 1997 16:28
>
> Clive:
>
> Well, _I_ can telnet to our SCO (3.2) just fine.  The dialog
> looks like:
>
>   # telnet scosysv 25
>   Trying...
>   Connected to scosysv.telamon.com.
>   Escape character is '^]'.
>   220-scosysv.telamon.com Sendmail 8.6.8.1/SCA-6.6 ready at Tue,....
>   220 ESMTP spoken here
>   quit
>   221 scosysv.telamon.com closing connection
>   Connection closed by foreign host.
>
> If you don't get the 220 messages, then you're not connected to an
> SMTP server, or it isn't working correctly.  Can you telnet from the
> 3000 to any other port on the SCO?  e.g. 23, the default for starting
> a telnet session?  If not, then there's some problem with the TCP/IP
> setup on your 3000.  As I recall, checksumming is an option on the
> 3000, and if the other system(s) require it, things won't work.  Check
> in NMMGR (I don't remember where) to ensure that the TCP/IP checksums
> are enabled.
>
> ------------
> Randy Medd
> Telamon, Inc.