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Questions tagged [rbl]

The tag has no usage guidance.

1
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1answer
78 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 ...
1
vote
1answer
120 views

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
1answer
137 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 ...
0
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0answers
9 views

How can I specify multiple servers to the ec_dns_lookup function in ecelerity?

In ecelerity, the sieve++ function ec_dns_lookup can optionally be passed the IP of a custom DNS server as an argument. This is used, for example, when querying an RBL server. We have multiple RBL ...
0
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0answers
104 views

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 ...
0
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1answer
646 views

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: ...
2
votes
1answer
163 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 ...
0
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1answer
135 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
1answer
378 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. ...
1
vote
0answers
137 views

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 ...
4
votes
0answers
90 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 ...
0
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0answers
268 views

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 ...
0
votes
2answers
73 views

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 ...
0
votes
0answers
143 views

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 ...
1
vote
1answer
723 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 ...
0
votes
1answer
30 views

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 ...
0
votes
1answer
265 views

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 ...
3
votes
1answer
572 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 ...
1
vote
0answers
369 views

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 ...
2
votes
1answer
393 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 ...
4
votes
1answer
2k views

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 ...
2
votes
1answer
841 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, ...
3
votes
1answer
955 views

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 ...
5
votes
2answers
24k 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=...
1
vote
1answer
514 views

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....
0
votes
1answer
431 views

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 ...
20
votes
4answers
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 ...
0
votes
2answers
706 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
1answer
220 views

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. ...
2
votes
3answers
220 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 ...
0
votes
1answer
784 views

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
1answer
57 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 ...
2
votes
1answer
262 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 ...
0
votes
1answer
286 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)...
0
votes
2answers
371 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. ...
0
votes
2answers
376 views

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 ...
0
votes
2answers
216 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
2answers
320 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?
4
votes
1answer
1k views

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 ...
1
vote
2answers
175 views

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
1answer
309 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 ...
0
votes
2answers
1k views

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 ...
7
votes
5answers
56k 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
2answers
411 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 ...
1
vote
3answers
75 views

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 ...
1
vote
1answer
69 views

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 ...
4
votes
1answer
15k views

Postfix Whitelist before recipient restrictions

Alright. Some background. We have an anti-spam cluster trucking about 2-3 million emails per day, blocking somewhere in the range of 99% of spam email from our end users. The underlying SMTP server ...
8
votes
3answers
23k views

Why is my email server in AT&T's blacklist?

I just got this bounce message: <████████@att.net>: host scc-mailrelay.att.net[204.127.208.75] said: 521-88.208.246.34 blocked by sbc:blacklist.mailrelay.att.net. 521 DNSRBL: Blocked ...
0
votes
2answers
486 views

What DNS Records / Zones are required for setting up a dnsbl server?

I'm trying to setup my own custom dnsbl server for blocking spam. I have successfully created a server running rbldnsd but am curious about what DNS records I would need to have in place so that my ...
0
votes
2answers
260 views

DNSBL Server - Linux Distribution Recommendations? [closed]

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 ...