Not able to send external email on Exchange 2003

Help needed urgently.

My Exchange 2003 suddenly not able to send external email, but incoming email is working fine.

It use to be working fine, but 2 days ago suddenly not able to send out external email. Anyone know or face this issue before?!

All my outgoing email is stuck in the Exchange Relay and no bounce back mail.

Thank you.
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XCONBLRConnect With a Mentor Commented:
Thanks for the screenshot. It should show some Additional queue information at the bottom of the page.
Could you check this once?
Also make sure that the domain is not blacklisted from mxtoolbox.
Also verify if you can submit an email from that server to Yahoo server (since the mail is stuck to using telnet. Make sure the telnet client is installed. If not, u can install it from add or remove windows components.

open command prompt

Telnet 25

You should be seeing a banner
Once you see a banner, type in
mail from: <>
rcpt to: <>
Subject: Test email... please ignore

Test email


Close the cmd prompt.
Check if the mail went through.
If your server IP is blacklisted, it will inform you during the telnet.
Manpreet SIngh KhatraSolutions Architect, Project LeadCommented:
Is there some Firewall ?
If you send an email to external does it shows in the Queues on the server or goes out ?

- Rancy
Alan HardistyCo-OwnerCommented:
Can you telnet to my server on port 25?

telnet 25

If not, try:

telnet 25

Any joy?

If not - talk to your ISP after checking your Router / Firewall for restrictions and make sure they have not cut your port off.

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AmitIT ArchitectCommented:
Sounds to be a DNS issue. As mentioned by Alan, check with your ISP, if any change made recently.
Pramod UbheCommented:
Also check if there is any network issue/blocking between your exchage server and front end server. In my case it was due to a wrong IPSec rule configured between fe and exchange server.
PJ_SohAuthor Commented:

Thanks for all the reply. Appreciate it. Yes, is connected with Firewall, had check & reboot the firewall, still same. Port 25 and 110 is open. I can connect to my exchange server and send internal mail from outsite using POP3 & SMTP.

I suspect is my Exchange server issue, but don't know how to find the root cause.

Please help.

Alan HardistyCo-OwnerCommented:
Have you rebooted recently?
PJ_SohAuthor Commented:

Yes, had reboot many times.
PJ_SohAuthor Commented:
Had activate the log and below are the log I got:

2013-01-04 08:43:29 OutboundConnectionResponse SMTPSVC1 KSD301-MX2 - 25 - - 421+4.7.1+[TS03]+All+messages+from+;+Retrying+will+NOT+succeed.+See+ 153 0 187 - - -

2013-01-04 08:43:29 OutboundConnectionResponse SMTPSVC1 KSD301-MX2 - 25 - - 421+4.7.1+[TS03]+All+messages+from+;+Retrying+will+NOT+succeed.+See+ 153 0 219 - - -
Alan HardistyCo-OwnerCommented:
Okay - please check your SMTP Virtual Server and SMTP connector settings, check if you are using a Smarthost and if you are, should you be and if you should, are the credentials set correctly?

Are the settings using port 25?
PJ_SohAuthor Commented:
The mail keep on retrying in the Ralay. Attach is the screen shot. But is in Chinese.


Outgoing mail stuck in Mail Relay
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