Mails blocked by magicspam for unclear reason

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WalterS
Posts: 2
Joined: Wed Nov 27, 2019 8:33 am

Mails blocked by magicspam for unclear reason

Post by WalterS » Wed Nov 27, 2019 8:36 am

Hello,
a customer got the message below. The admins of server dd25912.kasserver.com say there is no spam. Could it be that magicspam blocks the mail because of domain name kasserver.com?
The provider behind kasserver.com does run thousands of servers on that domain, so blocking this pattern is the wrong way.
Why exactly is the mail blocked?

info@***.de: host
mx***.***.de[79.133.**.**]
said: 550 5.7.0 Your server hostname [dd25912.kasserver.com] for IP
[85.13.145.3] matches a pattern which was abusive in the past. See
http://spamauditor.org/best-practices/check_reverse_dns_list/ for more
information. Protection provided by MagicSpam 2.0.18-1
http://www.magicspam.com (in reply to RCPT TO command)

magicspam
Posts: 1253
Joined: Tue Oct 28, 2008 2:27 pm

Re: Mails blocked by magicspam for unclear reason

Post by magicspam » Wed Nov 27, 2019 11:27 am

Hello WalterS,

Thank you for your post.

If you follow the URL in the rejection notice, you should find detailed information as to why your message was blocked.

It would appear that the reverse DNS record: dd25912.kasserver.com is known for sending spam in the past; to resolve this issue, we would suggest that the customer update their rDNS record to a static entry, something that better describes their server:

mail.kasserver.com

Please note that we are the developers of the software and not the operators of the email server. If the customer's messages has been blocked without just cause, please 'whitelist' them or reach out to the sender to update their rDNS record as mentioned above.
-- MagicSpam Support Team --

WalterS
Posts: 2
Joined: Wed Nov 27, 2019 8:33 am

Re: Mails blocked by magicspam for unclear reason

Post by WalterS » Wed Nov 27, 2019 12:40 pm

Hello and thanks for reply.
The domain kasserver.com is a domain of a big german hosting company, that is renting servers. All their servers do get a hostname with a subdomain like xyz.kasserver.com.
To block mails because of the domain kasserver.com is like blocking mails from thousands of servers that has nothing to do with each other, expect the same hosting company.
Please remove the pattern kasserver.com from the global blocklist and block each individual subdomain or each individual server if there is spam.
We do have other customers with different servers and hostname like xyz.kasserver.com that writing us that mails are blocked. This is not acceptable. Please change that.

magicspam
Posts: 1253
Joined: Tue Oct 28, 2008 2:27 pm

Re: Mails blocked by magicspam for unclear reason

Post by magicspam » Wed Nov 27, 2019 1:31 pm

Hello WalterS,

Thank you for your reply.

As per our previous post, we are the developers of the software and not the operators of the email server (or maintainers of the offending rDNS records lists) and as such we cannot remove this entry from the list.

If the company is renting IP space that was used by spammers in the past, they should update their rDNS records to more appropriate record for the email server:

e.g:
mail.domain.tld

This policy (check_reverse_dns_list) provides protection from spammers renting IP space just for spamming, in which case they do not care about setting up the proper rDNS entry.

If this is a legitimate server, the hosting company should be able to update the rDNS record for the given customer.

Alternatively, you can whitelist the sender or disable the following policy in your MagicSpam:

Block Mail Servers reported as Spam Source (NONDUL REGEX)
Rule Name: check_reverse_dns_list

However, please note that this might increase spam in your server from spammers who purchase used IP address space to send spam.

We hope this information helps.
-- MagicSpam Support Team --

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