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Blocked Email

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Not sure if this is the right forum as I'm new here, but I got the following meesage when trying to send email to a client (I've substitued their email address):

Your message did not reach some or all of the intended recipients.

Subject: Excel Courses

Sent: 03/06/2008 18:05

The following recipient(s) cannot be reached:

info[at]client.co.uk on 03/06/2008 18:05

There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.

<cyberstudios.co.uk #5.5.0 smtp;550 Rule imposed as PaulBrown[at]cyberstudios.co.uk is blacklisted on SpamCop (see www.spamcop.net)>

I only receive this message when emailing this particular recipient. Is the email being blocked at their end or mine?



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Most likely, the email is being blocked at your end. However, the phrase "PaulBrown[at]cyberstudios.co.uk is blacklisted on SpamCop" is very misleading, as spamcop does not list individual email address. Instead, spamcop lists IP addresses that are known to have sent spam in the recent past. That information should be included in any error messages produced by the recipients server.

My first suggestion would be to try to contact the postmaster at the receiving server about this problem. Often simply using "postmaster[at]domain.com", where domain.com is the domain of the email address you are having problems reaching, will work. Postmaster addresses are not supposed to be filtered, in accordance with RFCs, but sometimes they are. If that does not work, you could try sending and email from a free yahoo or hotmail account, or if you can find a contact phone number or a website for the receiving ISP, you could try those routes as alternate means of contact.

Further analysis:

cyberstudios.co.uk has MX record mail.cyberstudios.co.uk

mail.cyberstudios.co.uk has A record

Assuming that this is the same as the outgoing IP address (A big assumption, but one that is very often true for smaller organizations):


shows: not listed in bl.spamcop.net

So either that IP has timed off the list already, is not the correct outgoing IP address, or was never listed in the first place and the recipients server is producing a bogus error message.

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Thanks for your help. Do you think then that it could be that the recipient subscribes to a spamcop email service? As you say, our domain doesn't seem to be blacklisted and the only time I get this message is when we try to email this company. Today was our first contact with them; we replied to their business enquiry and after emailing them twice within an hour or so I'm wondering if we just need to be whitelisted at their end?

P.S. I meant to add that it is only our exchange server email address which is being blocked. If I change to a different account with direct access to our internet domain pop3 we can get through with no problems.

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Do you think then that it could be that the recipient subscribes to a spamcop email service?

The rrejection notice wants to imply that the SpamCopDNSBL is being used in a blocing fashion by the receiving ISP. First of all, this isn't the recommended usage by SpamCop.net itself. Secondly, as noted previously, the offered error message simply sucks, so there's even a further implication that even if the SpamCopDNSBL was in use, the 'filtering' rules on the receiving e-mail server may be seriously flawed, with the wrong error message sucked up for justification.

With this post, this Topic is being moved out of the SpamCop Email System & Accounts Forum section as there is no connection to the query raised and a SpamCop.net e-mail account .... There is the possibility that the SpamCopDNSBL may be involved, so that's where this Topic will end up.

As noted previously, further discussion on the situation will require more information, specifically the IP Address of the outgoing e-mail server that is allegedly being blocked.

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