Unable to send email to some domains

[AtomsTech]

Hello.

I'm providing IT support for a company using Exchange 5.5 SP3.

They are unable to send emails to a few domains. They can recieve email from those domains. The NDR message is "The receipient was unavaliable to take delivery of the message." I have called support for these domains to confirm they are not blacklisted. They also say the problem is on my end.

I have tried nslookup for all domains (good and bad) but get DSN timeouts.

If I try to ping the domains I get destination unreachable.

Any help would be great.

 

[bigdog92]

first of all i would upgrade your exchange to sp4 (alot of fixes there have done it recently myself). It sounds like your mail isnt getting out of your routers. I would check the configuration of your routers.

 

[kavita11]

I am having similar problems. I get the following error:

The recipient was unavailable to take delivery of the message
The MTS-ID of the original message is: c=US;a= ;p=MYDOMAIN;l=MYSERVERNAME -030424210339Z-312
MSEXCH:IMS:MYDOMAIN:Houston:MYSERVERNAME 3499 (000B09AA) Host unreachable.

I have upgraded to Exch 5.5 SP4 but it has not helped. I have checked my DNS settings on both Primary as well as secondary. We are not blacklisted either but still the mail does not go out. I have 2 email servers one outside my firewall one inside my firewall and both cannot send email to roadrunner domain, this is one of the main issues I am working on.I am still figuring this out. If you find anything please let me know.

Thanks
Kavita