Telent to

Posted on 2009-02-12
Last Modified: 2012-05-06
I'm having problems sending mail to a particular client, when I telnet from our server I get the following

250 Hello [my ip address]
250 OK <> Sender ok
250 OK <> Recipient ok
data (at this point is should normally say mail queue for delivery but I get nothing, it works fine when I send from another site, we are not on any spam list and can send mail fine every where else)
Question by:Sid_F
    1 Comment
    LVL 4

    Accepted Solution

    I've seen this before. Usually, it's because is doing some type of verification on the sender, such as a DNS lookup that is hanging. My guess is that when they look up your IP address's PTR record or your domain's MX records, that the lookup is hanging for them.

    Without knowing your actual domain and IP address and what verifications they're performing, it will be hard to determine why. However, usually it's because your MX records or PTR record is over 512 bytes, and's DNS is misconfigured not to allow TCP DNS connections for DNS queries with answers over 512 bytes.

    I would recommend contacting the recipient's e-mail server administrator offline and work with him or her to resolve the issue.

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