SBS 2011 Exchange using Positini has intermittent 500 RCP To Errors

Posted on 2011-04-23
Last Modified: 2012-06-27
Hi all,

I have recently migrated our office to SBS 2011. We wanted to get rid of the POP3 service and decided to go with Positini. I have all users setup on positini, mx records are passing the tests and setup. Watchguard firewall is using NAT translation from our outside IP address to the SBS server. I am using outside IP address for delivery on the inbound server. I have added the IP addresses for receiving mail on the internal sbs internet receive connector.

When I do the SMTP tests on the Positini site I am getting sucessful results but also getting the 500 error RCP To, check firewall or email server is down. This will happen randomly on any user. Also I am seeing these errors with the normal email as well. It is hit and miss. I am leaning toward something I am  not doing on the exchange connector.

Any ideas and thanks in advance!!! Also if I am leaving out some information that would be helpful let me know!!!

I sent an email just now went through. Sent again to another user here is the error message

 Unable to send SMTP message test: 550 - RCPT TO failed.  
 The email server is not available. Check your firewall or email server for settings that might be preventing delivery.  
Question by:jgartrell
    LVL 8

    Accepted Solution

    I had similar problems with postini.  I dumped it for mxlogic (just bought by mcafee):

    While I was troubleshooting with postini, I used authsmtp to bolster delivery:
    LVL 29

    Expert Comment

    by:Sudeep Sharma
    Hello jgartrell,

    Could you please post the exact error you are getting while sending the emails? Please remove the original domain in the post and put some dummy name instead.

    LVL 56

    Expert Comment

    by:Cliff Galiher
    Watch guard has some documented compatibility issues with exchange if you use their smtp proxy. When using exchange with watch guard, I recommend doing simple traffic forwarding without using tge advanced proxy filter.


    Author Comment

    Hey and thanks for the responses. I really appreciate the help.

    1) I am not getting a response from the tests as they come from I am waiting to get some test emails back from my personal account. It is very hit and miss on if they go trhough or not.
    2) I can test great from positini to my server all day with no issues.
    3) I have taken off the watchguard proxy. Thanks for the idea but it is still doing the same thing.
    4) Would a reverse dns problem  cause my sbs 2011 connector to not work correctly
    5) Should I put the ip addresses for positini in my connector setup? I already have but need to know if there is something I am missing.

    Thanks again.

    Author Comment

    Hey Everyone,

    Thanks for the initial repsonses. I have gotten everything put back to my old email for now. I have contacted Mcafee and will setup with them. Google has NEVER even called back on my ticket that I opened 7 days ago. I am going to cancel the postini and move to Mcafee. I called there support line before I even had an account with them and they were very helpful and responsive. I have a live account manager and support with Mcafee.

    Thanks for the referall npinfotech.

    LVL 8

    Expert Comment

    Thank you - I'm glad I could  help!

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