SMTP OR Reverse DNS issue

Discussion in 'Windows Small Business Server' started by kazi, Aug 16, 2006.

  1. kazi

    kazi Guest

    Hi folks
    I have just setup my SBS2003 Server. All incoming msgs are fine. May be 10%
    of outgoing emails come back with the following msgs.

    The following recipient(s) could not be reached:
    There was a SMTP communication problem with the recipient's email server.
    Please contact your system administrator.<myemaildomain.com> #5.5.0 smtp;550
    Dialups/open relays blocked. Contact <>> ,

    ******** OR **************************
    <mydomain.com #5.5.0 smtp;554 Service unavailable; Client host
    [xx.xx.xx.xxx] blocked using dul.dnsbl.sorbs.net; Dynamic IP Addresses See:
    http://www.sorbs.net/lookup.shtml?[ IP address of my MX Record ]

    Over all Network setup :
    Our server has private ip address[192.168.xx.xx] but have static ip on
    firewall and fwd port 25 to my server.That same wan ip of our firewall is MX
    record at our ISP as well. Do I need to make some changes in my default SMTP
    virtual server or have my ISP check on my RDNS ..

    Any help is appreciated ...
     
    kazi, Aug 16, 2006
    #1
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  2. sounds like your IP has once been used by spamming or is on a list by
    EarthLink

    the easiest way to fix this is to find out what your ISP's SMTP gateway is.

    Run ICECW and switch from sending mail via DNS to smarthost (Basically
    sending through your isp's SMTP gateway)
    and put that SMTP gateway there

    like SMTP.yourisp.com

    Russ

    --

    Russell Grover
    SBITS.Biz
    Enterprise Solutions for Small Business
    Microsoft Certified Small Business Specialist.
    MCP, MCPS MCNPS, (MCP-SBS)
    Portland/Beaverton Oregon USA
    Support @ SBITS.Biz
    Live Support with SBS2003
    http://www.sbits.biz/livehelp/
    http://www.SBITS.Biz
     
    Russ SBITS.Biz \(MCP SBS\), Aug 16, 2006
    #2
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  3. The reports you're receiving suggest that your public IP is considered to
    be part of a dynamic or dial-up range. Since you've removed your public
    domain/IP information (there's no good reason to do so), we can't help you
    check.

    Visit www.dnsstuf.com for a whole buch of DNS/IP tools that will let you
    find out the status of your IP.

    You may need to talk to your ISP about this, and if they're unhelpful, you
    may have to switch to using their mail server as a smarthost in Exchange
    (the CEICW can set this for you).
     
    Steve Foster [SBS MVP], Aug 16, 2006
    #3
  4. Steve Foster [SBS MVP] wrote:

    Oops, typo: www.dnsstuff.com with two ff's in stuff.
     
    Steve Foster [SBS MVP], Aug 18, 2006
    #4
  5. kazi

    kazi Guest

    Thnx for response.
    I've asked my ISP to setup PTR records properely and the results for rdns at
    www.dnsstuff.com are accurate. The wan ip is pointing to correct hostname.
    I've sent numerous emails to earthlink and also have spoken to their support
    telling the issue but they said their IT team is working to resolve the issue
    and will try to fix it in the next 72 hrs. I've also provieded them the email
    headers of NDR response as well. By monday morning i'll find out the response.

    Meanwhile I'm thinking to put my ISP mail server instead of fwding mail to
    dns servers in SBS2003 ciecw wizard. But just a thought that won't the
    earthlink server will still try to check back(their mysterious mechanism) to
    the originating email server instead of my ISP's smarthost and drop the mail.

    What is the best and safe way to check if my mail server is not a relay..

    thanks in advance..


     
    kazi, Aug 20, 2006
    #5
  6. Mail sent through your ISP's SMTP gateway will appear sent from them..
    (Your IP, but from their SMTP gateway.)

    If you want to test, set up SMTP and send a test message to an outside email
    account you have.
    then look at the Headers.

    SBS2003 is Default to NOT open relay, so you'd have to open it for it to be
    one.
    To check for Open Relay and A ton of other stuff. (BookMarke this or
    memorize it.)
    http://www.dnsreport.com/
    You can check Duplicate MX records etc.

    Open relay test.
    http://www.abuse.net/relay.html

    Russ


    --
    Russell Grover
    SBITS.Biz
    Enterprise Solutions for Small Business
    Microsoft Certified Small Business Specialist.
    MCP, MCPS MCNPS, (MCP-SBS)
    Portland/Beaverton Oregon USA
    Live Support
    http://www.sbits.biz/livehelp
    Support @ SBITS.Biz
    http://www.SBITS.Biz


     
    Russ SBITS.Biz \(MCP SBS\), Aug 20, 2006
    #6
  7. The ISP's mail servers will be the ones that have to pass Earthlink's
    tests, but email relayed through an ISP will still be labelled as from
    you. There'll be additional entries in the headers to reflect the path the
    email took from you to ISP to Earthlink to end recipient.

    I hope you're not suggesting that he should reconfigure SBS to be an open
    relay - the intended meaning of this comment is not completely clear.
     
    Steve Foster [SBS MVP], Aug 20, 2006
    #7
  8. NO Laugh
    OF course not.

    Meaning unless you Opened SBS to be an Open Relay.
    It's NOT buy default..

    But some people like to check anyway, because their BOSS says they won't
    proof..

    Also some people have servers that will want to open the SBS Box for
    Relaying.
    (Which is a Manual Process to open up now. thank God)

    -Russ



    --
    Russell Grover
    SBITS.Biz
    Enterprise Solutions for Small Business
    Microsoft Certified Small Business Specialist.
    MCP, MCPS MCNPS, (MCP-SBS)
    Portland/Beaverton Oregon USA
    Live Support
    http://www.sbits.biz/livehelp
    Support @ SBITS.Biz
    http://www.SBITS.Biz
     
    Russ SBITS.Biz \(MCP SBS\), Aug 20, 2006
    #8
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