(000B099C) Host Unknown <-- I get this error when sending mail

[klaxyn]

I have exchange 5.5 installed on win2k advanced server, with sp3 installed, running primary domain controller.  When I install internet mail service then all of a sudden I cannot send mail.  I get the error message pasted below.  Has anyone ever run into this problem before?  What should I do?  Let me know if you need more info.  Thanks.<br><br>-Kurin<br><br><br>Your message did not reach some or all of the intended recipients.<br><br>      Subject: <br>      Sent: 7/16/2000 1:38 AM<br><br>The following recipient(s) could not be reached:<br><br>      '<A HREF="mailto:klambert@ameritech.net">klambert@ameritech.net</A>' on 7/16/2000 1:39 AM<br>            Unable to deliver the message due to a communications failure<br> The MTS-ID of the original message is: c=US;a= ;p=EARTHmatrix;l=P504-000716053743Z-2<br>            MSEXCH:IMS:EARTHmatrix:EARTHMATRIX504 3902 (000B099C) Host Unknown<br>

 

[robocop]

I too have this problem.

what is worse I am able to receive mail via POP3 to our exchange server but am unable to send via SMTP.
If however I have a connection to the internet active - the email gets sent ok. If i do not have internet connection active I get the error messgage bounced back at me

HELP !!!


thanks

rob

 

[brontosaurus]

? Robo, if you don't have an internet connection, how do you expect to send mail outside? Or am I missing something? Perhaps you're using a demand dialer?

Klaxyn, assuming that you're also attempting to send mail to outside parties, please describe your DNS setup. I suspect that's your issue...

 

[robocop]

brontosaurus

We use an on demand dialler. Should't the exchange server store the emails as pending until the preset time for the dialler to dial out.

 

[brontosaurus]

Yes. Are you using straight DNS for lookups on the IMS (I guess so), or are you forwarding to a smart host? What DNS servers are you using?

 

[robocop]

I am forwarding to smart? host. - wait for it

mail.btopenworld.com

I think this is the problem. my knowledge on DNS could fit on a postage stamp.

any ideas

thanks

robo

 

[brontosaurus]

Actually, if you're demand dialing, it's better to use the &quot;Forward all Messages to host&quot; option. Usually though, you'll get better performance putting an IP address in there, but no big deal. Now, on the exchange server itself, what Primary DNS servers are you using on the networking properties of the NIC?