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Receive this message when I try to send external email<br />
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The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'bytron123@yahoo.co.uk'. Subject '', Account: 'mv', Server: '192.*.1.*', Protocol: SMTP, Server Response: '554 &lt;******123@yahoo.co.uk&gt;: Recipient address rejected: Relay access denied', Port: 25, Secure(SSL): No, Server Error: 554, Error Number: 0x800CCC79<br />
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Outlook allows to send mail from this email account sat in a DMZ to other internal accounts. &nbsp;I can also telnet to the SMTP server on port 25<br />
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Answers would be appreciated
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Receive this message when I try to send external email

The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was 'bytron123@yahoo.co.uk'. Subject '', Account: 'mv', Server: '192.*.1.*', Protocol: SMTP, Server Response: '554 <******123@yahoo.co.uk>: Recipient address rejected: Relay access denied', Port: 25, Secure(SSL): No, Server Error: 554, Error Number: 0x800CCC79

Outlook allows to send mail from this email account sat in a DMZ to other internal accounts.  I can also telnet to the SMTP server on port 25

Answers would be appreciated

Sneding external email from outlook locted in a DMZ on a firwall

Software firewalls, also known as host-based firewalls, provide a layer of software on one host that controls network traffic in and out of that single machine. Most operating systems now include firewall software, but many available software firewalls include central distribution, antivirus systems and disaster recovery.