have a customre whos doing a migration from 2k3 to 2k7 and after installing the 2 hub-cas servers in WNLB and then the 2 CCR clusters very perfectly and mail flow between the 2k3 and 2k7 internally and externally was very good suddenly he stoped beign able to send emails to any external domain from any user mailbox reside on the exchange 2k7 beer in mind that there is a RGC between the 2k3 and the 2k7 hub so the main guy is still the exchange 2k3 server the email going from the 2k3 reach the queue and got stuck there giving the follwoing error msg 451 4.4.0 primary target ip address responded with 421 4.2.1 unable to connect attemted failover to alternate host but that didnt succeed, either there are not alternative host or deleivery failed to allalternate hosts i tried also to send to hotmail.com , msn.com , yahoo.com also the same errori enable the verbos looging on the SMTP send connector on exchange 2007 i got this message in the log file alot 2008-12-25T11:55:57.349Z,Internet Connector 2007,08CB3494C6B14AC2,0,,65.54.244.72:25,*,,attempting to connect 2008-12-25T11:55:58.349Z,Internet Connector 2007,08CB3494C6B14AC2,1,,65.54.244.72:25,*,,"Failed to connect. Error Code: 10061, Error Message: No connection could be made because the target machine actively refused it 65.54.244.72:25" Ahmad Ramadan AbaYazeed

i already have on the exchange 2007an smtp connector with * address space and source server are my 2 nlb hub-cas servers and a cost of 10 and on the exchange 2003 i have the same connector but with cost of 1 i found out that when i create the exchange 2007 connector as i said the mails wont go from any exchange 2007 mailbox to the internet but wheni delete that connector the mail flow goes very smooth!! i am still waiting for any advice about this wierd problem waiting for replies!!! Thank youAhmad Ramadan AbaYazeed

refer to another thread:http://social.technet.microsoft.com/Forums/en-US/exchangesvrtransport/thread/059eef39-4b3c-4855-918c-cc41f789afc1/Mike

Hi Ahmed Ta7ya Masr ya 3m :) I have a problem like yours but simpler I have one exchange 2007 server holding all Roles antispam module installed Everything was working great but after my ISP Deleted my dns records by mistake my server IP address was black listed for a week after been removed from the black list I cant send emails to outside my domain and having your exact same error messages If you solved your problem you may can help me My email is: m_nagy77@hotmail.com You can add me to your MSN to chat about work problems if you want Thanks in advance

Ta7ya masr ya bashaaaaaaaaaaaaai added ya to msnha2olak el 7al eh when i see u :DAhmad Ramadan AbaYazeed