Probleem incoming e-mail

[aproost]

I currently have a problem with incoming e-mail.

=======================================
----- The following addresses had permanent fatal errors -----
<'jos@1234.com'>
(reason: 550 Host unknown)

----- Transcript of session follows -----
550 5.1.2 <'jos@1234.com'>... Host unknown (Name server: 1234.com': host not found)
========================================

Does somebody have any idea about the problem and what sollution is.

 

[58sniper]

It's clearly stated in the error message. Either 1234.com doesn't exist, or it can't find it (which would be a DNS issue).

Pat Richard
Microsoft Exchange MVP
Contributing author Microsoft Exchange Server 2007: The Complete Reference

 

[Zelandakh]

Could be connector, namespace or relaying. Without knowing more about the inf I can't tell.

What have you changed since it was working?

 

[ChicagoRookie]

Suggestions are following
- re-confirm the intended recipient's address,
- Resend your message to the corrected address.

I guess that this means that mail server was not able to locate the mail server for 1234.com. (mail.1234.com) in the Internet's domain name service (DNS).

If the target system can't be found in the DNS, then our mail server can't connect to the remote mail server to deliver your message.

Most "host unknown" errors are caused by a typo in the domain name part of the intended recipient's address, but an increasing number of "host unknown" errors are the result of trying to reply to junk mail (spam).

This is because the "From:" address on junk mail is almost always bogus. Where the address is typed correctly and is a real one, the problem is usually a temporary failure in DNS.



CCNA & NETWORK+
My every answer is
"There seems to be no pattern of when this problem occurs."
for Users..

 

[aproost]

The problem is the quote after the domain : 1234.com'

The only thing that has been changed is an new provider and an Netasq Firewall has been installed.