We help IT Professionals succeed at work.

Check out our new AWS podcast with Certified Expert, Phil Phillips! Listen to "How to Execute a Seamless AWS Migration" on EE or on your favorite podcast platform. Listen Now


Email server 450 host down

stewartje asked
Medium Priority
Last Modified: 2007-12-19
We are running Groupwise 6.5 on a windows 2000 server.  It has had no problems until about one month ago.  We keep seeing the follwoing message in our Groupwise Internet Agent logs:

11:50:02 10 DMN: MSG 413 Send Failure: 450 host down (yahoo.com)

The host down has been several different domains but one has been an external email address that we use as a back up email account.  We have contacted the provider and they say everything is working ok on their end and it must be our problem.  

Additionally even though the email server reports the host down, the email sent to that domain does get to it, occasionaly.

can someone help out.??

Watch Question

Your mailserver looks up the DNS entry available to it for yahoo.com and then attempts to contact this address to see if the address is available. If the address that your GWIA discovers via MX lookup is down or unavailable at that moment, you will see a 450 host down error (which is true).

Your server will then query the next available MX record for yahoo.com and attempt to send to that address until all the MX records it can find are exhausted. At that point your message is deferred and will delivery will automatically be re-attempted for 4 days (I think this is the default for 6.5). After 4 days the message is discarded and an undeliverable message is returned to the sender.

This is functioning as designed, and is perfectly normal. You are merely seeing the console logging in action.




i was afraid that was going to be the answer.  can you shed some light on on why only two domains, an email provider for our back up email and now our own domain is reporting the following:

421 SMTP service not available, closing transmission channel and then 450 host down. (domain XXX.XXX)

Is it possible that UUNet, our T1 provider,  does not have the correct MX record for xxxx.net and XXXX.com?  How can Groupwise report that our own domain is down?  

I can accept your answer I just want to make sure that I am explaining our situation properly.  Thanks

Unlock this solution and get a sample of our free trial.
(No credit card required)



Ok.  I am confused I thought the hosts file is nto used anymore.  I have an entry in my local DNS, mydomain.com and is set to my Server LAN IP.  
Is this what you suggest I do?

Sorry for my tardy response, I've been a tad busy lately.

The HOSTS file modification will stop your server from ever having to look up its own domain. I ALWAYS put this entry in for my mail servers. Why waste the time doing a lookup when this box IS the domain I'm trying to look up? I move a LOT of mail through my gateways, so every few milliseconds I can keep makes me that much more efficient.

Your DNS setup is correct, I am not faulting it, I merely prefer this method for speed and to ensure that my mail server ALWAYS knows that it is MYDOMAIN.COM regardless of whether or not I lose connectivity to my DNS server and my DNS is busy.

Try adding an entry and see if your problems get better, if it does not, then remove it and we can look for something else.



Ok.  Thanks.  I added the domain to my hosts file.  

Can you offer advice as to where I could locate a good forum or usenet for Groupwise?   I have lots of questions and have not been able to find a group that can answer them.

Novell post their own forums and they are trolled by the sysops for each product.
You will generally get better answers to your questions here at EE, but the Novell forums are free.

The server for the Novell forums is : support-forums.novell.com They ofer this in both NNTP and web based formats.




thanks for the answer I apprecaite it very much.

As for the current problem, the hosts file has been modified to include mydomain.com but I am still getting the the following:

09:00:25 6 DMN:MSG 426 Send Failure: 450 host down. (mydomain.com)

09:00:41 0 MSG 427: Response 421 SMTP service not available, closing transmission channel

How do I fix this?

Unlock the solution to this question.
Thanks for using Experts Exchange.

Please provide your email to receive a sample view!

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.