SMTP protocol error occurred

220 pts.
Tags:
Exchange 2003 error messages
Microsoft Exchange 2003
SMTP connector
SMTP Errors
HI, We have a problem with our external mails.Frequently our external mails we stuck in queue and it will not connected to the remote servers.It gives "SMTP protocol error occured"in the additional information for the queue. Once we restart our exchange server then the mails in the queue will be delivered and the external mails will work fine for few days. This is happening very often to us and i cant find the exact reason for this problem. Someone please help me to find and resove this issue. Thanks

Answer Wiki

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Check your event logs for SMTP errors and post the exact errors. If you have not installed SP2 and all rollups and exchange updates install these as soon as possible. How long ago did the problem begin? What changes were made before the problem began?

********
One thing that occured to me after reading over the discussion… If you are running Exchange on Server 2003, make sure that you have all available microsoft updates installed. Last year I was having issues with people getting too many logins on the exchange server and was able to determine that there were issues with the scalable networking pack with server 2003 which was not compatible with some network cards and the fix was to disable the tcp chimney with the command Netsh int ip set chimney DISABLED. This is all explained in <a href=”http://msexchangeteam.com/archive/2007/07/18/446400.aspx”>this article</a>.
This problem was resolved with another microsoft update which was released well after this problem was discovered which disabled this feature and is mentioned at the beginning of that article. Perhaps this may be causing your issue.
~technochic

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  • Exchstart
    I have checked our SMTP logs but could not found any error log in it. This problem started 2 month back and after restarting the SMTP services we did not get this issue for few weeks but now it once again started . No we have not done any changes in our exchange.
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  • Clarke
    I have a very similar issue...I cannot send mail to a few domains that had been OK before. This started about 6 weeks back, right after Dec 1. I get "An SMTP protocol error occured" in the Exchage System Manager, but no other details. I have tried settting up diagnoistic logging to Maximum, but I still get no other details, and nothing in the Event Viewer. If I delete the message with NDR from EMC, the NDR gives me SMTP error #4.3.2, indicating a problem on the receiving end. When I lookup this error in my MS Technet, it says the problem is a frozen queue on my server.
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  • Exchstart
    Hi, Someone please give me the solution for this issue, our external mail queu is getting stuck every two days and we are not able to send and receive external mails until we restart our front end. Thanks
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  • Robert Stewart
    I have seen this type of behaviour on an Exchange server that is out of space, is your total mailstore bigger or near the size you have allocated for the mailboxes? I ask this because a restart in this type of environment usually gives you a couple more days before locking up again. Just an idea for you to check if you have not already. I hope this helps you out.
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  • Exchstart
    Hi Robert, Thanks for your responce, i have not checked it but i will do it now.
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  • Exchstart
    Hi Robert, I had a good look on all my Backend and front end Exchange servers but there is no issue of Mailstore limit as ours is Exchnage 2003 there is no limit for the mailbox store and the servers are not out of space.I think there is some other issue that Im not able to find out. Please anyone kindly help me to solve this issue.................
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  • Robert Stewart
    Maybe we can get Technochic in on this, she seems to be an Exchange guru. Technochic any suggestions on this one??
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  • NedK
    Hi, Getting very similar symptoms from about 2 months ago. Using SBS2003 - iSP BT All emails sent from exchange sit in output queues then fail arter multiple retries states 'SMTP protocol error' No other erorrs recorded even with enhanced diagnosticsenabled. Very occssionally some will get through after many hours.
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  • Exchstart
    Hi guys, I enabled all the options in Diagnosting Logging and find the event id when the error occurs. Its Event ID 7002 :Smtp Protocol and it says, ID 7002 reads: This is an SMTP protocol warning log for virtual server ID 1, connection #1060 The remote host 65.168.34.131, responded to the SMTP command "rcpt" with "451 Requested action aborted:local error in processing". The full command sent was RCPT To:<email address>" This may cause the connection to fail. I had a search on the MS forum and it says, To resolve this error, try one or more of the following: Make sure that the latest network card drivers and firmware are installed. Run any network diagnostics software that was supplied with the network cards to verify that the network cards are functioning correctly. If the network cards are configured to automatically detect the speed of the connected network, change the configuration to use a specific speed setting. For additional information that may help you resolve this problem, see Microsoft Knowledge Base article 153119, XFOR: Telnet to Port 25 to Test SMTP Communication. Please let me know if you find some other solution for this problem.
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  • NedK
    Hi, While the additional diagnostics might give a clue I find it difficult to believe it's a potential NIC card software/driver issue. I run SBS which obviously runs a number of applications on the same server inc ISA. At no time do i suffer any other network interface issues it's only emails sent directly via the exchange server that I have a specific issue with. I can in fact quite happily send emails via works stations using POP3 via the SBS/exchange server, it's only SMTP that appears to have the issue. I'm assuming people here are using email ISP's other than BT as I've been experiencing a number of other email issues with their service for several months.
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  • Robert Stewart
    Have you tried what the Knoweldge Base says regarding testing via telnet?? "For additional information that may help you resolve this problem, see Microsoft Knowledge Base article 153119, XFOR: Telnet to Port 25 to Test SMTP Communication." I would try and test when email is piling up in that queue, just a thought and sorry you have not gotten anywhere with this problem, If you have problems with the telnet test it is probably the mail server setup. Hope this helps
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  • Exchstart
    Hi Robert, I have not tested the telnet thing when the mails got stuck, coz it happens in the working hours and users will suffer if they did not get mails, so i just restarted the server as soon as possible. But any how i will try the telnet next time. Could you tell what will be problem if the telnet does not work? Thanks
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  • Robert Stewart
    Not off the top of my head, I'm sorry I'm really not an email guru, technochic seems to be, she has alot of helpful posts throughout this blog on email. My first response to this post was due to your problem was very similar to a problem I had with an exchange server, same issues being described, and mine was my exchange server was out of space! It was weird, if I rebooted it would buy me 48 hours of time before the queue locked up again. Have you called Microsoft?? That would be my next step if Technochic cannot help. Again I'm sorry and I feel your pain, nothing like having faulty email program. Keep your head up someone has your answer.
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  • Exchstart
    Hi Robert, Thanks for your support, i will try and get he solution as soon as possible. Good Luck to you, Thanks
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  • Exchstart
    [...] Exchstart [...]
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  • Exchstart
    Hi Technochic, I downlaoded the fix from the microsoft but not sure whether to install it on our server.In the article it's mentioned that this network compatibility problem occured in Server 2003 sp2 but we have server 2003 sp1 and exchaneg server 2003 sp2 in all our Front end and backend servers. So, do i need to install it in server 2003 sp1. I have tried using Ex Best pratice analyser to check the issue and i got a warning in front end as our network card drivers are 2 years old and need to be upgraded.Can i do it in front end and check it, will there be any issues ?
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  • Technochic
    Definitely update your network card drivers, that's important. And starting with the front end servers is always the best practice with Exchange, although that usually relates to Exchange updates, still it doesn't hurt to start there. As far as the fix, you are correct in that the problem was introduced with server 2003 SP2 and the scalable networking pack, so if your servers do not have server 2003 SP2 then that is not what is causing your issues. If you do update to SP2 then apply all subsequent updates as well to keep this from becoming the problem. Since the Scalable Networking Pack with SP2 is not likely to be your probem I highly recommend you get on a support call with Microsoft about this.
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  • NedK
    HI, I too have run the Exch best practise and the only questionable concern is the network driver updates but as the main NIC is an on-board driver which is running the latest driver software but is over 2 years old. I'm reluctant to purchase a separate NIC. I have little doubt the problem only started occurring around the time I installed EXC SP2. Strange though that after a few weeks of total SMTP mail failures I have now started receiving a few again as it was back in December but they are usually many hours behind. It also appears that a good proportion of the mails are sent during or shortly after a reboot then it hangs again.
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  • Ashley5
    I cant open up any of my emails - yahoo, hotmail, outlook. Email properties say that SMTP is an unknown protocol. How do i fix this? Any help with this problem would be greatly appreciated. http://www.fixoutlook.net . this site solve some problem.but some issue remain here.so please advice me.
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  • ITKE
    Hi Ashley5, Please post your question as a new thread in IT answers. You'll get a quicker and more thorough response that way. Thanks and good luck!
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  • Stolengtr
    did the original issue ever get resolved? i have this exact same issue and would love to know what the solution was if it was resolved! thanks!
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