5.7.1 IP address denied-4  -  CompuServe NDRs!

Posted on 2005-04-26
Last Modified: 2008-01-09
We have a MS Exchange 2003 server that recently started having this problem.  Every time we email anyone we get this NDR withing seconds of sending the message:
Your message did not reach some or all of the intended recipients.

      Sent:      4/26/2005 8:32 AM

The following recipient(s) could not be reached: on 4/26/2005 8:33 AM
            You do not have permission to send to this recipient.  For assistance, contact your system administrator.
            < #5.7.1 smtp;550 5.7.1 IP address denied-4>

We also have some issues emailing AOL (owner of compuserve), but the NDR doesn't get returned immediately with AOL like it does with Compuserve. AOL's take a few days of trying to send before getting returned.

If you do a Google search for "5.7.1 IP address denied" the ONLY results you will get are about Compuserve!  So, what I need is either someone who knows why Compuserve is blocking us from emailing them OR a good contact for Compuserve so we can find out why were being blocked.

I have attempted to call their regular Tech Support line and talked to someone who told me I couldn't speak to tech support unless I was a member and that I should have the member who can't receive email from us call in.  Well, ANYONE who is a member won't be able to receive email from us, but the tech didn't care.

At this point, any help you can offer may help.  Thanks!
Question by:tebacher
    LVL 15

    Expert Comment

    Hi tebacher,
    It looks like your IP address has ended up on some sort of spam black list.

    Take a look at and see what it comes back with.

    Also, make sure that you have a PTR record (reverse DNS) set up for the IP address that your mail server is sending from.
    You can check this at

    Does that help?
    LVL 6

    Author Comment

    I did look into the blacklists.  I searched every blacklist site I could find, but we weren't on any of them.  We aren't on any at

    Also, we do have a PTR record in place...

    I just found out from someone who had this issue before that AOL forces you to get on their whitelist before you can send them email!  We must have gotten blocked before (we didn't have a PTR for a while) and now we must get un-blocked!  

    I'm going to attempt to call AOL's support for this.  Does anyone have an actual contact number for this type of thing I can try instead of just the regular tech support number???
    LVL 4

    Accepted Solution

    AOL has their own Blacklist.

    Go here to see if you are on it.
    LVL 104

    Expert Comment

    If you are on a dynamic IP address or DSL connection then you will almost certainly have problems getting email delivered to AOL and other ISPs. You will have to route your email through your ISPs SMTP Server using an SMTP Connector.

    LVL 6

    Author Comment

    I found out that we are on AOL's block list.  I was able to find this out by using Telnet based on these instruction:

    The telnet connection from my mail server was refused, with an error code an a link to AOL's site explaining that error.  So, now I know what is happening, and I just need to call AOL to get OFF the list!

    I'll report back with what happens there and close the question then.
    LVL 6

    Author Comment

    Sembee - it's not a dynamic IP or a DSL connection, but thanks for the suggestions!
    LVL 6

    Author Comment

    I spoke with someone in the Postmaster team at AOL and they are going to take us off their block list.

    I'll award the points to easy-v as the link given was exactly what I needed!  It lead me to the Telnet test that, in turn, showed me that we were being blocked and how to fix it.

    So, thank you, easy-v, and thanks to everyone else who gave suggestions!

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