smtp dns name rdns mail

Discussion in 'Windows Small Business Server' started by Dru, Apr 22, 2008.

  1. Dru

    Dru Guest

    still having so many problems, mail getting blocked by yahoo, hotmail,
    comcast, etc etc etc.

    i have had rdns setup ok... my isp did another adjustment.. they forgot a .
    at the end of the names...

    god it never ends.

    here is my question:

    in SMTP when the email servers do their HELO,

    my sending server says hi, im ns1.domain.com
    the receiving server checks rdns to see that that domain and ip match rdns.

    SO, where do i edit the name the exchange server identifies itself as
    externally.. i need to check it.. "ns1.domain.com" ???

    thanks!
     
    Dru, Apr 22, 2008
    #1
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  2. Dru

    Dru Guest

    i see the exchange logs show for its own server name, the computer name here
    locally, like you'd see in local network.

    i need to change it to ns1.domain.com

    thanks
     
    Dru, Apr 22, 2008
    #2
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  3. Dru

    Steve Guest

    SMTP VS properties advanced delivery tab.

     
    Steve, Apr 22, 2008
    #3
  4. Dru

    Dru Guest

    lastly lol,

    we have two domain names we send mail for.

    the rdns for the ip of the mail servers are associated with 1 domain.

    my question, if we have going out, and the email server
    is saying hi im ns1.domainA.com. is that a problem?

    i have a txt entry that lists authorized mail servers. although the only
    listed MX on each is our receiving SPAM filter service servers.

    so our sending mail servers are not listed in MX ... that used to not be a
    problem!
     
    Dru, Apr 22, 2008
    #4
  5. Dru

    Joe Guest

    A problem with no definite answer, as a mail server can be configured to
    reject on a wide variety of grounds.

    The absolute minimum, I think, is:

    -HELO/EHLO string can be resolved by public DNS i.e. has an A record
    somewhere on the Internet. So it must be changed from the default SBS
    machine/local domain name.

    -Sending IP address has a reverse DNS (PTR) entry.

    -The PTR record content can be resolved by public DNS, and the IP
    address associated with its A record is that of the sender, i.e. there
    is a complementary A/PTR record pair attached to the sending IP address.

    -Not being on a blacklist. A fixed IP address helps, but isn't a guarantee.

    So far, few mail hosting companies (Comcast is alleged to be one)
    require that two or more of the HELO string, the PTR record and the MX
    record for a domain should match. This requirement may become more
    common, which is silly, as quite a few businesses send mail from a
    different IP address than the one used for receiving. Large companies
    have many public IP addresses and often separate have send and receive
    servers, and many small companies use external spam-cleaning services.
    Many companies also operate more than one domain, and while an IP
    address can have multiple PTR records, some DNS lookup software cannot
    deal with a list.

    Apart from the basic mechanics, people like Yahoo are becoming much more
    aggressive over content. I had trouble sending instructions on VPN
    setup, which contained URLs, to a client's employee recently. They're
    never going to beat the spammers by content filtering, but they're going
    to block a lot of genuine mail before their customers have had enough of
    their clients being treated like criminals for daring to want to send
    them emails. I wouldn't mind so much if 'yahoo' didn't feature quite so
    often in my reject mail log.
     
    Joe, Apr 23, 2008
    #5
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