I recently installed a RedHat Enterprise Linux system. I have sendmail, with cyrus being used for pop3 with outlook clients on my PCs.

The problem is that When I send emails from outlook to any external domains, I get the following error:

The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'fred@digicorp.com'. Subject 'Fw: Welcome to Outlook Express 6', Account: 'citygate.com', Server: 'citygate.com', Protocol: SMTP, Server Response: '550 5.7.1 <fred@digicorp.com>... Relaying denied', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79

To test my install, I used Telnet to port 25. Using this connection, I successfully created and sent an email to an external domain. I also used the regular Linux mail command to send emails to external domains without any issues.

It appears that the problem only occurs if I am using outlook and I am sending to an external domain.

At this point I am pretty much baffled. Any suggestions would be greatly appreciated.

It appears that the problem only occurs if I am using outlook and I am sending to an external domain.
So your thread should not be in Linux - Server, but in the "General" forum...


At this point I am pretty much baffled.
Could this help?: http://support.microsoft.com/?id=290808

As best as I can tell the problem is with the Linux server. The outlook clients have been around for several years and working fine with the previous RH 8 Linux server.

Also the microsoft help deals with outlook express vs. outlook. In my case both outlook and outlook express behave in the same way. Able to send email to the local domain but not to external domains.

Thanks

Hi,

in your server settings for the mail-account check "smtp-server needs authentication".
Maybe your smtp is configured to accept relaying only for authenticated users.

HTH

Moved: This thread is more suitable in the General Forum and has been moved accordingly to help your thread/question get the exposure it deserves.

Can you elaborate on where I might look for the server settings for the mail-account.

This is a Vanila installtion of Redhat Linux. Is this a setting which would by default be set.

thanks

Hi,

you have to switch this setting in every Outlook-Client.

Menu Extras/Accounts/Server

Another possibility is to allow unauthenticated relaying on the server.
But this can result in mailing for spammers.
Or allow relaying for the localnet only.
Maybe this was the setting for your old server.

HTH

Tried to set the client to authenticate when sending emails. But it did not make any difference.

I can't belive this is such as difficult thing. I simply downloaded and installed Redhat and enabled sendmail to talk with external hosts per instructions on RH website, same as I did before with RH 8.

Any addtional thoughts would be greatly appreciated.

Thanks