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Help with 451 4.4.0 Primary target IP address responded with: "421 4.2.1 Unable to connect.
Greetings!!!
451 4.4.0 Primary target IP address responded with: "421 4.2.1 Unable to connect. I have a scenario that I have old exchange 2003 server which is still using to send the email and the new exchange server 2007which has all the mail boxes. I could not change it until I sorted out with Symantec mail security.
Mails are going to 99% domains but not going to very few domains and for these domains the above message coming. If someone could help in this regard.
Could it be due to some SPAM black listing on these sites. I have also check www.mxtoolbox for blacklisting and it does not mention any site which blocks our domain.
451 4.4.0 Primary target IP address responded with: "421 4.2.1 Unable to connect. I have a scenario that I have old exchange 2003 server which is still using to send the email and the new exchange server 2007which has all the mail boxes. I could not change it until I sorted out with Symantec mail security.
Mails are going to 99% domains but not going to very few domains and for these domains the above message coming. If someone could help in this regard.
Could it be due to some SPAM black listing on these sites. I have also check www.mxtoolbox for blacklisting and it does not mention any site which blocks our domain.
Hey ican help u but i am not at my desk so please wait r go to my profile and see answerd quetions thanks
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SOLUTION
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r u using cisco pix router?
ASKER
Resolved the issue
Try to resolve their MX from you Exchnage server.
Open command prompt and type :
nslookup -type=mx domainname.com
(where domainname.com is a domain for which you receive 421 4.2.1)
Compare the mx record (with mxtoolbox) and what you get from ping mx.domainname.com returned by you mail server nslookup to see if records match
Regards.