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.

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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'...
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1 vote
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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 ...
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1 answer
293 views

what matters MTA's IP or hostname or both

There is no proper single article or I haven't researched properly, to find what does matters most for MTA's reputation IP or the hostname of the MTA or both matters equally. I am asking this question ...
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google apps domain gives diffrent servers when emailing out then mxtoolbox search shows

When I search a domain that uses google apps I get 10 results mx servers for the domain. similar to this alt1.aspmx.l.google.com alt2.aspmx.l.google.com when I recieve emails I get completly ...
0 votes
3 answers
107 views

Sharing IP black lists

Are there any tools similar to fail2ban that would allow sharing of IP black lists? What I'm looking for is something similar to a DNS based blackhole list or real-time blackhole list as is used to ...
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2 votes
1 answer
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How do I know if an abuse report about unsolicited is actually about my server?

I received an Abuse-Message from the operators of dnsbl.de. To me it sounds like it has nothing to do with me, but since it is too serious I don't want to do "guess work" and check whether it really ...
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5 votes
2 answers
641 views

Postfix: ACCEPT if RBL and SPF checks pass, DUNNO/greylist otherwise. How to do it?

I would like to accept all clients that pass RBL and SPF checks (and possibly some checks, but these are minimum requirements for me), and greylist those who don't. When a client passes the SPF check (...
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1 vote
1 answer
317 views

How to get postfix to check all 'Recieved:' headers against an RBL?

I have several rbls listed in smtpd_client_restrictions, but this only checks the client IP against the RBLS. Is there any way to get postfix to check each Recieved: line against the RBL like ...
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1 vote
1 answer
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Find an IP that is known to be on a DNSBL

I am configuring Zabbix to check my IPs against several DNSBLs. My IPs are currently not blacklisted. My monitoring needs to be tested, to verify that it will alert properly if one of my IPs does ...
1 vote
1 answer
529 views

IPBlockListProvider vs. IPAllowListProvider

I am using Spamhaus SBL and Spamcop as RBL providers in Echange 2016 which works fairly well for me. However, some connections are blocked which really shouldn't. To prevent false positives I went on ...
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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 ...
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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: ...
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2 votes
1 answer
434 views

DNS server in RBL

While SMTP servers should not be on RBL, to ensure deliverability of emails, what about DNS servers themselves? Does it matter? I am asking this question because multiple Route53 DNS servers are on ...
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1 answer
679 views

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 ...
1 vote
1 answer
839 views

Postfix - Skip RBL checks after a SPF Pass

I've started using policyd-spf and am using the following recipient restriction. What I'd like is for senders that pass the SPF check to skip any RBL checks. Unfortunately that's not happening. ...
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1 vote
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How to RBL block forwarded email in postfix?

I have RBL blocking successfully configured in postfix, using reject_rbl_client in the smtpd_recipient_restrictions section. However, I use a mail forwarding service through which I receive some spam ...
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3 votes
0 answers
110 views

Combating a persistent spam list

We use Office 365 as our primary mail provider. We have an internal mail server that we use for relaying things like reports from our SSRS, scan to inbox for old scanners, etc. It is an IIS SMTP on ...
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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 ...
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2 answers
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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 ...
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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 ...
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1 vote
1 answer
1k views

Bounce mail blocked by Trend Micro Email Reputation Service

When I tryied to send an email, the following error appears: 200.123.99.139 does not like recipient. Remote host said: 550 5.7.1 Mail from 67.222.38.55 has been blocked by Trend Micro Email ...
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0 votes
1 answer
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Losing headers from Relay server

Trying to troubleshoot spam filtering. I have a relay setup to accept all my incomming emails and filter them before it hits the main server. I cant seem to get spamassassin to put the headers in for ...
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0 votes
1 answer
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SpamAssassin stops RBL DNS-based tests after some time

I faced the problem with my email server: too much junk mail because of failing DNS RBL (SURBL, URIBL) tests. I prepared test message with SURBL test URL and checked it with "spamassassin" binary and ...
6 votes
2 answers
2k views

Spamassassin: Bypass /etc/resolv.conf DNS for querying DNSBL?

Question Is there a way to let spamassassin bypass my linux system's dns servers to query DNSBLs? Background Info When my Server receives email, it is checked by spamassassin. One of this checks ...
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Is there a way to configure postfix to bypass spam/RBL checks on a particular destination hostname or username?

I'm running Postfix on CentOS 7, a fairly generic implementation, but I do employ some RBL checking on incoming mail. I like using SORBS for example but I have a few clients who seem to have issues ...
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2 votes
1 answer
628 views

check spamassassin DNSBL results

Is there a way to check the results of spamassassin on an email when it checks DNSBL? I see nothing in the maillog and nothing in the mail header. I do not know if it is actually querying the DNSBLs ...
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5 votes
1 answer
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How Does DNSWL work? How can I gain better trust? [closed]

How does DNSWL work? It's clear to me when someone report a spam, but how can I gain a higher score/trust? Do some companies report "good" servers? Or will the score go up with time without reporting ...
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2 votes
1 answer
1k views

Does postfix cache RBL queries?

This is driving me nuts… Linux Debian + postfix… /etc/postfix/main.cf has the following lines: smtpd_recipient_restrictions = check_recipient_access hash:/etc/postfix/access, ...
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3 votes
1 answer
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Configure Barracuda Spam Filter behind Postfix to use client IP when do RBL-checking

I have the following setup: Internet -> Postfix Mail setup as Proxy -> Barracuda Spam Filter -> Microsoft Exchange I have tried searching through the documentation and configuration panels to see ...
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7 votes
2 answers
31k views

How to enable RBL checking in postfix?

How to enable RBL filters in postfix? My current configuration: submission inet n - n - - smtpd -o syslog_name=postfix/submission -o smtpd_tls_security_level=...
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1 vote
1 answer
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mod_security RBL - apparent false positive

I'm struggling with an RBL rule in mod_security under apache 2.2 that seems to be giving me a false positive. I see the following in the audit log (IP address redacted): Message: RBL lookup of 4.3....
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1 answer
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URIBL_BLOCKED on Ubuntu 14.04 Server with working Dnsmasq

I've set up a small mail server which includes Spam Assassin. Everything seems to work great except one. SA docs suggest installing a caching DNS server to keep some RBLs from blocking the server over ...
21 votes
4 answers
3k views

What are the best methods for catching snowshoe spam?

I'm using Smartermail for my small mailserver. We've been having a problem lately of getting waves of snowshoe spam that follow the same pattern. They come in batches of 3 or 4 at a time. The ...
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0 votes
2 answers
1k views

Exim - block incoming mail from blacklisted IPS only

I would like to check for blacklists only for incoming e-mail. I have users who usually get dynamic IP's which are blacklisted so they are not able to send the e-mail if I turn the blacklist option on....
0 votes
1 answer
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Windows 2012 Essentials DNS problems querying certain RBLs

I'm running a mail server, Smartermail (SM) on Windows 2012 Essentials. The server is also doing DNS, but has no other roles. The DNS server is using the root hints and has no forwarders configured. ...
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2 votes
3 answers
326 views

is there a PAM module for DNSBL lookups?

I have been enumerating the remaining security concerns on one of my back-end production servers, when I came to the realization that something which could be incredibly useful was missing from my ...
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1 answer
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Installed RBLDNSD for making a custom RBL but something is missing, could you help us?

We have successfully installed RBLDNSD with the idea of having a custom RBL server. Now we have started to make some testing adding some IPs to the our blacklist, and also have configured Exim (Cpanel ...
0 votes
1 answer
67 views

Evaluation of mail server configuration

I have a mail server configured to use DNS real-time blacklists (DNSRBLs), e.g. zen.spamhaus.org, to determine whether delivered email is spam or not. I would like to evaluate my mail server's ...
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2 votes
1 answer
610 views

Postfix thinks IP is in blacklist, but is not actually listed in blacklist

Got a bit of a weird problem here with Postfix. Been getting a whole bunch of notices where fail2ban has banned 69.164.196.21 (ryujin.darkdna.net) for failures against Postfix. Here is a relevant ...
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1 answer
332 views

Postfix - RBL check behind relayhost

We are running a mail server which is responsible for a sub-domain (say, dom1.example.com). All the mails sent from Internet are received through our relayhost (mail server responsible for example.com)...
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2 answers
452 views

SMTP / HELO and RBL black listing

We've been having many issues with our external IP address being put on RBL's and blacklisted. We are using a 3rd party, hosted SMTP e-mail and we have two locations using it. Our TLD is ABC.com. ...
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Why does mail, from some domain, sent through someisp.com, get blocked by the isp's webserver being listed in RBLs? [closed]

Today I one of our customers forwarded to me a mail from the ISP of one of her mail recipients that says they're blocking my customer's email because our webserver IP is listed in some RBLs. Of ...
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0 votes
2 answers
219 views

How often do MXLogic lists get updated?

Some domain refused to accept email from my domain due to MXLogic filtering. I've sent an email to falsepositives@mxlogic.com and they responded promptly that they changed their records. Question: ...
2 votes
2 answers
344 views

Monitor IP for RBLs

Is there any way to monitor an IP against RBLs. I want to have an alert over email when my IP is blacklisted in any RBL over internet. Any help?
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Which RBL's does sophos use?

Anyone know where I can find the a list of which RBL's Sophos use's? I have checked their website with no luck, and currently awaiting a response from their technical support. Thank You in advance ...
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1 vote
2 answers
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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) ...
1 vote
1 answer
399 views

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 ...
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2 answers
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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 ...
11 votes
5 answers
79k views

How do I remove IP from sorbs.net blacklist?

Our email server has ended up in the sorbs.net blacklist and we're going round in circles trying to get it removed, currently this is causing down-time between our suppliers. I am a developer and not ...
6 votes
2 answers
437 views

Which DNS Black Lists would you recommend to discard spam in pre-queue?

There are many black lists out there, with bad and good reputations. Also, some people recommend to use RBL lists only in score-based systems (like spamassassin) while others (including commercial ...
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