3 sites with exchange set up.
we will call the sites site1, site2, and site3.
I am in the example at site 3.
From site 1, we wish to communicate an email to site 2 - email sent to site 2 from site 1.
Approximately 50% of the time, messages are delivered and 50% are lost. Site 1 does not get any reponse back to indicate the message has been bounced, blocked or failed to deliver.
If I send a message to site 2 and site 3(me) on the same email from site 1, site3 (me) receives the mail everytime, but site 2 only received 50% of the emails.
If I send a message to site 2 and site 3 on the same email from site 1, and request a delivery receipt, again, site 3 (me) receives them all, and site 2 only about 50%. Also, site 1 receives receipt messages from site 3 (me) for all messages, but also site 1 also receives receipt message for some message that weren't delivered to site 2, and also doesn't receive receipt messages for items that were delivered, and also some receipts for messages that were delivered (hope that makes sense!)
To say I am a little consufed is an understatement.
Have checked on spamcop and spamhaus for the IP address's of site 1 and site 3 and neither are listed as blocked.
Antispam filters have been removed off firewall on site 2 but this has made do difference.
Any ideas on what else I can check?