Users sending from a external Exchange 2000 SP4 organiation are trying to send my users mail. They are the only ones that we cannont recieve mail from. And they say we are the only ones they cant send to. The event log displays this message when ever they try to send a email.
Inbound authentication failed with error LogonDenied for Recieve connector Default EXCAHNGE. The authentication mechanism is Gssapi. The source IP address of the client who tried to authenticate to Microsfot Exchange is [216.xxx.xxx.xxx].
My organization uses Exchange Server 2007 with Roll up 4
My questions are... Why would a external exchange server try to authenticate directy to my server in order to send mail?
How do i fix this either internally or by contacting their IT department?