- command: xexch50, response: 504 Need to authenticate first, full command: xexch50 976 2
From a newsgroup posts:
- "Your server is talking to another Exchange server and it tried to send the XEXCH50 command. Your server, quite correctly, refuses to accept that command from from unauthenticated connections.
Since you cannot stop your server from advertising the XEXCH50 keyword in response to a EHLO command there's nothing to be done."
- "Exchange 2003 only accepts XEXCH50 protocol data from clients who authenticate and have been granted "Send As" permission on the receiving SMTP virtual server object in the AD. It is expected that Exchange 2003 will block inbound XEXCH50 data from other Exchange organizations by default, and in this regard the fact that it is responding with "504 Need to authenticate first" is actually correct, if the remote server is not part of the same Exchange organization.
If you're seeing this between servers in the same Exchange organization, that is potentially an authentication or ACLing problem that should be looked into. You can use ADSIEdit.msc to investigate the ACLs of the Exchange objects in the configuration container if you suspect that the necessary Exchange server security groups have not been granted the Send As access that they need on the SMTP virtual servers.
If you're seeing this between servers in different Exchange organizations, it is normal expected behavior, and should not actually block mailflow.
When Exchange 2003 rejects an inbound XEXCH50 attempt, it allows the client to continue without the XEXCH50 data. When Exchange 2000 or 2003 attempt to send an XEXCH50 command and are denied, they continue to try and send their message data."
- command: helo, response: 501 5.5.4 Invalid Address, full command: "helo <host name>"
From a newsgroup post: "This problem may occur if the sending server is not in accordance with the Request for Comments (RFC) 821 and RFC 1869 documents. The receiving Exchange computer expects either a host name only or a fully qualified domain name (FQDN) following the EHLO/HELO command. See ME291828
, "501 5.5.4 Invalid Address" error message from a sending UNIX server."
An example of host name that may cause this kind of problem is "mail.altairtech.ca.". The trailing dot after .ca is not accepted by the Exchange server. See ME291828
for an workaround this issue.
From a newsgroup post: My server was sending "lhr-mail (Internet FAX)" as host name in the "helo" command. I solved the issue by removing the host name from the configuration file on the smtp document scanner. According to Panasonic, this is a known issue and they instruct Exchange users not to use the host name parameter.