Welcome to the mailbox.org user forum!

mailbox.org reject harmless messages as spam without warning the receiver.

5870762 shared this idea 2 years ago

A lot of incoming email are silently rejected.

This must be fixed for mailbox.org to be used.

Senders received a bounce message looking like this:

<user@mailbox.org>: host mxext1.mailbox.org[] said:

> 554 5.7.1

> Service unavailable; Client host [] blocked by RBL;

> Blocked -

> see http://www.spamcop.net/bl.shtml? (in reply to RCPT

> TO

> command)

This means that mailbox.org reject a harmless message as spam without warning the receiver.

The reason of this major bug is a psychorigid implementation of SCBL.

From SCBL itself:

The SCBL is aggressive and often errs on the side of blocking mail.

When implementing the SCBL, provide users with the information about

how the SCBL and your mail system filter their email. Ideally, they

should have a choice of filtering options. Many mailservers operate

with blacklists in a "tag only" mode, which is preferable in many


Please correct immediatly.

Comments (1)


First of all: This has to be fixed by the owner of that IP. If this IP is on a Spamcop blacklist it is there for a very good reason. This is not a false positives. And as I just checked: The owner took care about his problem and the IP was removed and is not on the list any more.

Here's nothing to fix for us. And Spamhaus is doing a great job.

If you dislike RBLs and don't believe to that: Please go to the settings page and disable RBL-Checks for your account.


Hello Peer.

Thank you for this quick and accurate answer. I may have been excited.

With the message sender we will try to understand how to handle the problem. It is not a spam but a message sent by the president of an association to its members who are very numerous. Only mailbox.org rejects the message, it's still annoying!

Do not you have a way to soften the Spamhaus verdict?

I note the ability to disable RBLs.

I will come back after analyzing the thing deeper.


Please Peer help me to understand:

It seems that the IP address is the one of a server of Free Telecom!

It is is correct it is totally absurd to block it! It is used by a great number of Free customers.

IP Address

Fwd/Rev DNS Match Yes

Hostname smtp4-g21.free.fr

Domain free.fr

Network Owner Free SAS


It's not the message, it's the source IP address of the system that *WAS* (!) sending Spam. And "spamcop" is not just "something", it's the anti spam service from Cisco. It's propebly used by more then 50% of all e-mails.

If the message of the presidant of an organisation is very important, this organisation must take care about it's infrastructure like it is an important infrastructure. And it the mail relay is unsafe and blcoked worldwide (!) by one of the the most used RBL, they have a problem.

No, it's not only mailbox.org rejecting those messages. That's for sure not true. I know that, because I build personally many thousend ISPs and mail relays in Germany and Europe, even the "real big" ISPs. And I know what's best practice out there and I know who has written the books that have been read by most postmasters out there.

One big difference is, that mailbox.org (and the ISPs maintained by us) REJECT those messages, so that the sender (!) is informed that his message have not received the recipients. Other ISPs filter those mails info a spam folder, so that the sender doesn't know anything about his problem and also the recipient normally doesn't find the message there, so that -- at the end of the day -- the message is "lost" in 95% percent.


It is is correct it is totally absurd to block it! It is used by a great number of Free customers.

No, it is not. And even companies like Free Telecom does use RBLs by themselve to check inbound traffic.

All ISPs must (an do) care about their outbound spam traffic and must monitor and react if they're source of Spam. Blocking those systems is nothign else then quarantine "real people" in a hospital if they're infected and a danger for everybody. Doesn't matter if they are a president of something -- if they're infected (eg: Sending Spam/Viruses/CryptoViruses), they're quarantined (eg: blockd).

Sending Spam and also Viruses is a huge problem and produces *real* damage. Already forgotten about CryptoLocker? Those sources of those mails must be stopped/blocked until the source of this spam is cleared, which mus the done by the source ISP.


It's better that mailbox.org rejects the message with the explanation "blocked by RBL" rather than classifying it spam because at least you are warned that there is a problem!

The worry is that a French non computer scientist cannot understand!

Can you add to the bounce message a sentence like this:

  1. This message is classified as SPAM

which is much more readable?


No, I don't want to do that.

1) The message is NOT classified as spam. Especially because the content of the message never reach the destination systems if a client connection is blocked by RBLs. We haven't said anything about the content at all.

2) If a Server (!) is blocked by RBLs, the Source IP address has a bad reputation and is actually sending Spam and Mailware (and also normal messages, sure).

An internet user of today must understand the absolute minimum basics of an internet. You also need to understand the "busy signal" when you try to use a phone. I case of any questions, the SOURCE postmaster is the appropiate ressource to get support. That's what you have your mail account, that's where you pay your money, that's where you can decide if you have choosen good or bad ISPs and if you have good or bad experiences while using the Internet.


  1. 1) The message is NOT classified as spam.

True. Another clear and "english multilingual" sentence should be find, including the word SPAM: Your mail server is identified as SPAM sender.

  1. An internet user of today must understand the absolute minimum basics

False. I am not an "end user" of Internet and I needed your efforts to understand part of this problem. Not even in dreams an end user would try to understand a such bounce message. You should add a clear title.

  1. you can decide if you have choosen good or bad ISPs and if you have good or bad experiences while using the Internet

Todo. I agree that Free Telecom is a weak ISP. I agree that mailbox.org is a smart ISP. I cannot make it clear. You should help me too!