SMTP error from remote mail server after RCPT


A problem i have here, which so far as far as i have got from the ISP is that it is a server problem is causing greif.

basically, a client has a mail server accepting emails on domain
i have added as an additional email address, and in exchange, it accepts both and

the domain on the server is , i have made the primary SMTP email address, so emails send out as
the ISP has added to the DNS mx entry so all emails, and are sent to the server.

the problem i am having is that 3 or 4 clients are experiencing problems emailing the server,
the rest dont.
So on the general, the setup works fine, and when it doesnt it bounces back to the sender with this header.


A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:
    SMTP error from remote mail server after RCPT
    host []: 554 <>:
    Relay access denied


the setup was done about 3 months ago, so it isnt a propogation problem,
the ISP has said its the server

please help,.

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Its possible that your ISP has added net HOSTS that relay mail to your exchange server.

I think your SMTP service hase been set to recieve email from only specific IP addresses, this is good as it stops your exchange server acting as an open relay. Ask your ISP for a list of IP addresses that will be sending mail to your server and then check that there all listed on the relay restrictions on your SMTP virtual server.

-Open Exchange System Manager
-Navigate to <organisataion> -> Administrative Groups -> <site> -> Servers -> <server> -> Protocols -> SMTP
 -Right Click Default SMTP Virtual Server
- Click the access tab
- Click the relay button
- check the IP addresses against your ISP's relay servers

typo in the fist line, I meant new hosts not net hosts!

I've seen this problem here in North America where a mail server is hosted on a DSL line and certain hosts cannot deliver mail to them.  The resolution is setting our MTU to match our ISP's, in our case it is 1492.  Perhaps you are running into a similar problem?
Problems using Powershell and Active Directory?

Managing Active Directory does not always have to be complicated.  If you are spending more time trying instead of doing, then it's time to look at something else. For nearly 20 years, AD admins around the world have used one tool for day-to-day AD management: Hyena. Discover why

itbasementAuthor Commented:
techs from ISP are looking into it still

they havnt fixed it yet, but are looking in the direction of a secondary mail exchage error
Well, I guess that will fix the symptoms of the problem, but still won't fix or explain the underlying issue.
itbasementAuthor Commented:
was a secondary mail exchange configuration error
PAQed with points refunded (500)

EE Admin

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.