Cas to CAS connectivity: Intra-Organization SMTP

[Paul]

I have just added another CAS in a remote site. When emails are sent between
my original CAS and the new one, I am getting this error in my SmtpSend
transport logs:

Outbound Authentication failed with TargetUnknown

Looking at the Queue Viewer, I am also receiving this error for the "SMTP
Relay to Remote Active Directory Site"

451 4.4.0 Primary target IP address responded with: "454 4.7.0 Temporary
authentication failure." Attempted failover to alternate host, but that did
not succeed. Either there are no alternate hosts, or delivery failed to all
alternate hosts"

[Mark Arnold [MVP]]

On Fri, 8 Jun 2007 09:32:08 -0700, Paul
<Pa...@discussions.microsoft.com> wrote:

>I have just added another CAS in a remote site. When emails are sent between
>my original CAS and the new one, I am getting this error in my SmtpSend
>transport logs:

Emails don't go between CAS servers, they go between Hub Transport
servers.

>
>Outbound Authentication failed with TargetUnknown
>
>Looking at the Queue Viewer, I am also receiving this error for the "SMTP
>Relay to Remote Active Directory Site"
>
>451 4.4.0 Primary target IP address responded with: "454 4.7.0 Temporary
>authentication failure." Attempted failover to alternate host, but that did
>not succeed. Either there are no alternate hosts, or delivery failed to all
>alternate hosts"
>

What authentication methods are active/enabled on the send and receive
connectors on both HT servers? Do they match?

[Paul]

For the Receive Connector on port 25, both servers are set to:
Authentication: TSL, Basic, Exchange Server, Integrated Windows authentication
Permission Groups: Exchange users, Exchange servers, Legacy Exchange Servers
& partners

Those are all checked on both servers, and I triple checked them ;) Rebooted
remote site CAS server a couple times as well.