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Questions tagged [rbl]

Real-time Blackhole is a database of IP addresses known to send spam, accessible over DNS, with specific responses to determine whether a host should be rejected or allowed.

A Domain Name System-based Blackhole List (DNSBL) or Real-time Blackhole List (RBL) is an effort to stop email spamming. It is a "blacklist" of locations on the Internet reputed to send email spam. The locations consist of IP addresses which are most often used to publish the addresses of computers or networks linked to spamming; most mail server software can be configured to reject or flag messages which have been sent from a site listed on one or more such lists. The term "Blackhole List" is sometimes interchanged with the term "blacklist" and "blocklist". https://en.wikipedia.org/wiki/DNSBL

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Are there any tools for comparing DNSBL effectiveness?

I just added a new DNSBL to the list of ones that I use on my small mailserver. I set it up to be first on the list because I wanted to see what it missed but other lists caught. I'm watching mail logs out of the corner of my eye while I do other…
user10501
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How can I receive mails from otherwise blacklisted servers?

On the mail servers I set up in our company, I use several blacklists in postfix. These really help take care of the spam we get send our way. But every once in a while one of our (potential) customers can't send us mails because they are on such…
Oliver Salzburg
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How to skip DNSBL checks for authenticated main in Exim4

I have the following ACL with Exim4: acl_check_rcpt: deny message = DNSRBL Access denied - $sender_host_address \ listed by $dnslist_domain\n$dnslist_text dnslists = zen.spamhaus.org : b.barracudacentral.org This…
Jauzsika
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check_client_access and RBLs

In an attempt to better fight spam, I've configured Postfix like this: smtpd_client_restrictions = check_client_access hash:/etc/postfix/client_whitelist reject_unknown_client smtpd_recipient_restrictions = permit_mynetworks, …
Laurent Nominé
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does it still have any sense to directly drop mails that trigger RBLs?

Once upon a time, using RBLs to drop mails was actually a good idea. These days seems it is no more possible for a reason or the other, so every one switched / is_switching to just use RBLs as another test in score based antispam solutions (read:…
Luke404
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Connection Filtering with Multiple DNSBL's?

Is there any advantage or disadvantage to using multiple DNSBL's with ones connection filtering? I just switched from SpamHaus to BarracudaCentral but have added in SpamHaus to test for increased effectiveness. So far there is no dip in performance…
JohnyD
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Postfix no longer rejecting emails based on spam block lists

My postfix server is configured to reject emails based on a couple of spam block lists administered by spamhaus and spamcop. After noticing that I've been receiving more spam than normal recently, I've discovered from logs that the last time an…
Darren
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After adding a new DNSBL to Sendmail, how can I resubmit an email to see if it will be rejected?

TL;DR How can I fool my own sendmail into thinking an email comes from a particular ip address, so that it rejects the message due to a DNSBL match? Details: I run my own mail server, and most spam is blocked by the DNS black lists (DNSBL) that I've…
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DNSBL Server - Linux Distribution Recommendations?

I'm preparing to build a publicly accessible DNSBL server. Which Linux distribution would you recommend for something like this? I'm mainly interested in: General security Stability Resource utilization
Mike B
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Postfix NOQUEUE reject messages do not contain reason for rejection, why?

I have a postfix setup similar to ISPconfig.org's ruleset. Because of a failing RBL (SERVFAIL DNS response), Postfix rejected many incoming messages with a 451 4.7.1. type temporary failure instead of reporting the real error message: NOQUEUE:…
Jens
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How to test postfix DNSBL whitelist?

How can I test if my postfix whitelist works correctly (assuming I don't have access to any address currently listed on dnsbl). I'm not sure if my whitelist works ok. Here's my config: smtpd_client_restrictions = permit_mynetworks, …
Sfisioza
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IP on postfix whitelist is still blocked

Because an specific IP is often von a black list provider I have to put this IP on a whitelist because there are too many false-positives. I configured it some time ago and I am a Windows Administrator - so I am not that fresh in this subject…
Markus Schuhmacher
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setting up my own RBL server for postfix

I would like to setup my own rbl server for use with postfix. Caching The rbl server would reach out to a list of rbl servers. I would also like to be able to collect stats to see if rbl servers are worth having on the list. If it had too many…
cybernard
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Spam getting through despite being listed on an RBL?

Our spam filter (Vamsoft ORF) is configured to look at zen.spamhaus.org among a few others. This morning, I had a mailbox full of spam. As part of my normal procedure, I opened the email, read the headers, got the remote IP (199.116.118.190), and…
DrDamnit
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Generic way to download DNS Blacklist

I am looking for a generic way to download (multiple) DNS blacklists. The reason is that I would like to cache them locally for faster lookup. The lookup is not for an MXer, but for a log analysis tool. This tool will dedup IPs, so I will lookup…
Isaac
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