Can anyonehelp? On my exchange server, the Local delivery boxes kept filling up (both sources [regular SMTP & 400 Relay]). Rebooting Exchange server would clear it for a while, and then they would start filling up again. Diagnostic Logging would show numerous 7004 and 7010 errors for the MSExchangeTransport source. The 7004 errors varied from - "This is an SMTP protocol error log for virtual server ID 1, connection #XXXX. The remote host "IP Address responded to the SMTP command "rcpt" with "550 <edited>... No such mailbox. The full command sent was "RCPT TO :<edited>". This will probably cause the connection to fail. to This is an SMTP protocol error log for virtual server ID 1, connection #XXXX. The remote host "IP Address", responded to the SMTP command "rcpt" with "550 <edited>: User unknown ". The full command sent was "RCPT TO:<edited> ". This will probably cause the connection to fail. to This is an SMTP protocol error log for virtual server ID 1, connection #XXXX. The remote host "IP Address", responded to the SMTP command "rcpt" with "550 Unknown local part edited in <edited>". The full command sent was "RCPT TO:< edited > ". This will probably cause the connection to fail. The 7010 errors varied also from- This is an SMTP protocol log for virtual server ID 1, connection #XXXX. The client at "IP Address" sent a "xexch50" command, and the SMTP server responded with "504 Need to authenticate first". The full command sent was "xexch50 2356 2". This will probably cause the connection to fail. This is an SMTP protocol log for virtual server ID 1, connection #XXXX. The client at "IP Address" sent a "helo" command, and the SMTP server responded with "501 5.5.4 Invalid Address ". The full command sent was "helo H<:". This will probably cause the connection to fail. (NOTE: Had LOTS of this one with the same IP Address, the only thing that changed was the connection #.) This is an SMTP protocol log for virtual server ID 1, connection #XXXX. The client at "IP Address" sent a "helo" command, and the SMTP server responded with "501 5.5.4 Invalid Address ". The full command sent was "helo <7". This will probably cause the connection to fail. There is a single purpose PC set up as an email relay for connecters to mail sites that had been giving problems (hotmail, msn, aol, yahoo, and a relayetc...). The only active connector nowis called relay (we've fixed the others). For months (since I started working here), this set up was working. Suddenly on the 1st of Nov, the "local delivery" boxes would not send out anything. Rebooting the Exchange server would send them out, rebooting the relay PC would send them out, but this was a temp fix. After a bit they would build again. My supervisor had found something online about setting the "Send Helo instead of Ehlo" in the connector advanced property tab. After that we still got the error msgs (not as many) but everything would go through. Now if I haven't thoroughly confused everyone (as much as I am), my question is - Why after months of running properly did we need to select "Send HELO instead of EHLO" to get things running again? I don't think it could be updates as the last time I ran them on the servers was the 14th of Oct with no new ones since them. To my knowledge, no other changes have been made to the Exchange server or any of the others. Any and all help in understanding this !@#$!@#$!# would be truly appreciated. I thought I knew a little about Exchange when I started here, now I find how little I do know. Thanks in advance to all who help me out.

Looks like you are receiving a lot of spam messages? It is normal that Exchange takes longer to deliver local messages when under heavy load Configure IMF on Exchange http://support.microsoft.com/kb/907747 Or install another anti spam solution in front of your exchange server Deli

Are yousaying that the amount of spam increased enough over a 24hr period to bog down my exchange servers' local delivery?Then why did selecting "Send HELO instead of EHLO" in the connector advanced tab start thing running right again? Repeating whatI had sead, everything had worked finefor months till 1 Nov. This is what is confusing me.

Sending HELO instead of EHLO only helps in remote delivery when the remote system does not support ESMTP http://technet.microsoft.com/en-us/library/aa996090.aspx You can verify the queue length with performance monitoring But it can be possible to overload your system with bogus email messages for which your server needs to send NDRs but remote system does not exist Deli

Getting the same messages. What if NDR's are turned off? Would it still bog down the server?

If you switch off the NDR, you won't be sending out non delivery reports to systems that does not exists, so you will save your server resources. However if you receive tons of spam your server can be overloaded just from processing those email ( it is not likely to happen but you did not supply any details except one sentence that you have similar errors). BTW. digging up 3 years old thread without marked answer is not the best idea. If you have problem collect all the details and put it into new forum postWith kind regards Krystian Zieja http://www.projectenvision.com Follow me on twitter My Blog Need help with your systems?