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17
votes
5answers
5k views

Use IPtables or null route for blacklisting about 1 million IP addresses?

I've come across a situation where a client needs to blacklist a set of just under 1 million individual IP addresses (no subnets), and network performance is a concern. While I would conjecture that ...
14
votes
2answers
911 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 ...
12
votes
3answers
856 views

How to remove ourselves from nudity blacklists? [duplicate]

We recently bought our domain. It turns out, two generations ago, it was a porn site. Now we're still blocked in some filters, resulting in blocked pages at several corporate routers. I'm now ...
8
votes
4answers
22k views

Whitelist allowed IPs (in/out) using iptables

I have a few ip ranges to which I want my server to able to connect and users to connect from. Everything else should be blocked. How should I do that with iptables? My OS is Debian based linux ...
6
votes
2answers
2k views

Getting a domain name off of the blacklist

I have a friend who purchased a domain name recently that he found out (after buying it) is apparently blocked by many corporate firewalls or proxies b/c it's been tagged as porn by the blacklist db ...
6
votes
2answers
249 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 ...
5
votes
2answers
17k 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 ...
5
votes
4answers
4k views

How to report spam to blacklists

Is there a central place to report spam to various blacklists ? I regularly report to spamcop, but I do not see the addresses I reported as listed. (I guess nobody else bothers with my regular ...
4
votes
5answers
3k views

Best way to use large IP blacklist to deny access to a web server?

Is there efficient and easy way to use IP blacklist (like this one, but perhaps 2-3 times larger, which can't be simplified to CIDRs much) to deny access to a web server (either lighttpd or Apache) ...
4
votes
2answers
3k views

Refuse to send email to specific recipients with Postfix

So, right now I am halfway through trying to setup an outgoing-mail blacklist, by way of smtpd_recipient_restrictions. The problem I am experiencing is that my test emails are being delivered when I ...
4
votes
3answers
770 views

Customer's IP Listed on RBL - What steps do you use to prevent black listing?

Customer called saying their e-mail was bouncing from particular vendors. Investigated it and identified they were listed on more than one RBL/CBL. Restricted firewall to only allow traffic on port ...
3
votes
2answers
2k views

hotmail blacklist and rDNS questions

My company has recently purchased a VPS for email and webhosting. I am not an expert on email authentication but here is my story. After the VPS was purchased we started receiving bouncebacks with ...
3
votes
2answers
86 views

SMTP: Which IP should I monitor?

I use a relay server to deliver external mails. I use relay server's IP in SPF record. But I'm not sure about blacklist monitoring/checking. Should I check main server's IP or relay's IP?
3
votes
2answers
1k views

Unable to delist from SORBS blacklist [closed]

The IP address of one of my servers has been blacklisted by SORBS. The delisting process on their website does not work correctly for me. Asides from contacting SORBS directly, is there anything ...
3
votes
2answers
4k views

Gmail.com detect mail as spam, but the server is not on any BlackList

I have an issue with Google. (GMail to be exact) About 1 month ago, we had a security breach, and mail was relayed through our servers. we got listed in almost ALL Black-Lists :( we fixed the ...
3
votes
3answers
1k views

Postfix restrict recipients

how can I configure postfix to allow sending to a certain (external) domain only? I'm already using check_recipient_access. Content of my /etc/postfix/recipients_restrictions: domain.com OK My ...
3
votes
5answers
2k views

How to check, if IPs in your network are blacklisted?

I would like actively monitor, if any of my network IPs are on blacklists. Here I would like to collect links to instructions, how to sync blacklists, which allows that.
2
votes
2answers
5k views

Blocking apache access via user agent string

I've got a scripter who is using a proxy to attack a website I'm serving. I've noticed that they tend to access the site via software with a certain common user agent string (i.e. ...
2
votes
5answers
909 views

Blacklisting: IP's or domains?

I am implementing a blacklisting system on my website that monitors contact forms for suspicious usage (both spam content and excessive frequency). When I find somebody / robot that meets my criteria ...
2
votes
4answers
8k views

How do I get my server off the ivmSIP/24 blacklist?

I checked my server IP using this tool: http://www.mxtoolbox.com/SuperTool.aspx It's come up on the ivmSIP/24 list. What can I do to get my IP removed from this list? I have SPF records set to ...
2
votes
6answers
593 views

Eliminate Email Blacklist by switching IPs and Servers

We are a legitimate company. We have had some issues in the past with Virus attacks/ Spam bots getting our email server blacklisted. After the most recent attack I have been tasked at coming up with ...
2
votes
2answers
51 views

Are only IP-Addresses Blacklisted or also Domains?

Unfortunately one of the forms of my website was used to send completely sensless spammails. As I found out through "http://mxtoolbox.com" that my IP-address is listed on two blacklists, I want to set ...
2
votes
3answers
4k views

Email Server IP Address is Blacklisted

we have a Zimbra Mail server that was being used for 2 months now. the last week we faced a problem that the Public IP that was being used for our mail server started to be blacklisted and we couldn't ...
2
votes
4answers
806 views

Best practices on how to send emails on clients behalf and avoid being black listed

I am starting a business providing some online customer relationship management functionality. I want to allow my clients to create their own email lists. I also want to allow my clients to be able ...
2
votes
1answer
78 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 ...
2
votes
1answer
155 views

How do I implement IP-based export restrictions for my data stored on Amazon S3?

A little background: Corporate wants to make our downloads unavailable to U.S. export-restricted countries like North Korea, Iran, Syria, etc. Restriction by IP-block is considered good enough. (Yes, ...
2
votes
1answer
181 views

Will using google apps emailhosting get rid of blacklisting caused by a shared server account?

a client`s email addresses are constantly blacklisted due to other users who share the same server. the hoster does want him to switch to his own dedicated server, so he gets his own ip. my question ...
2
votes
1answer
450 views

How does IP blacklisting work on virtualized/shared hosting?

I have read that many blocks of IP addresses associated with Amazon EC2 have been blacklisted by various ISPs. Therefore, even if you never sent spam yourself, emails you send from an Amazon instance ...
2
votes
2answers
5k views

CBL This IP address is HELO'ing as “localhost.localdomain”

I am pretty lost here, my server somehow got into a blacklist. And I don't know why and how to solve it. Please take a look at the link below. CBL List - click here Anyone knows what is going on ...
2
votes
1answer
246 views

Postfix: Resend 'hard' bounces

I had a number of messages get rejected by the recipient's mail server with a status 550 code due to an IP address blacklist. I've sorted the problem that caused the host to become blacklisted, and ...
2
votes
1answer
484 views

How to whitelist CloudFlare IP ranges within iptables rules (multiport)?

There seem to be many different ways to setup whitelist rules within iptables. What is the wisest way to whitelist the CloudFlare IP address ranges below via SSH? 204.93.240.0/24 (204.93.240.0 - ...
2
votes
3answers
250 views

Reporting Suspicious Traffic

Is anyone aware of a web service that allows people to publish ip addresses as having run vulnerability scanning tools to determine the signature of the target? I would like to have a scheduled job ...
2
votes
1answer
95 views

at what level modprobe operates ? - linux

I have a machine with Ubuntu 12.04 64 bit, i have the need for blacklisting a module, i have blacklisted it in blacklist.conf but nothing happened; i have solved my problem passing ...
2
votes
2answers
1k views

Blacklist preventing DNS lookups?

To make a long story short, some users at another company who I have a lot of email correspondence with started having problems sending me email, they would get a message from the mailer daemon at ...
1
vote
5answers
310 views

IP address blacklisting program

Are there any IP address blacklisting programs for Linux servers that allow the administrator to specify certain conditions that trigger an iptables blacklist on IP addresses scanning for ...
1
vote
2answers
1k views

Where to place Nginx IP blacklist config file?

I have an Nginx web server hosting two sites. I created a blockips.conf file to blacklist IP addresses that are constantly probing the server and included this file in the nginx.conf file. However ...
1
vote
2answers
198 views

Mac server infected with spam agent

We have a huge trouble :( .. Our mac server makes a spam delivery. Our IP already blacklisted in about a dozen of servers (checked with http://mxtoolbox.com/). We have another computers in the same ...
1
vote
3answers
2k views

How to go about deploying batches of 5,000 emails?

I have been warned that sending too many emails too quickly can trigger an internet email blacklist/spam filter. I have a list of approximately 5,000 customers that I want to send a newsletter to. I ...
1
vote
1answer
410 views

Blacklisting Specific From and To with Postfix

I have a scenario where I need to blacklist emails from one email to one of our local emails. Is blocking this specific scenario possible in postfix? For example, emails from person@fromaddress.com ...
1
vote
2answers
1k views

Can i create a website blacklist with Group Policy?

Like i can create "whitelist" functionality for blocking all sites and allowing some via the GP setting: "User Configuration > Windows Settings > Internet Explorer Maintenance > Connection/Proxy ...
1
vote
3answers
420 views

Recommended way to use black list

How do you setup blacklists for Microsoft Exchange 2003? For example, RBL or CBL lists mitigating known spam. Is it recommended to maintain several blacklists together? If so, is there a set that ...
1
vote
2answers
24 views

Will a mail relay be blacklisted if it accepts a mail relay request then later sends NDR?

Got a question about blacklisting behaviour. Internet MX records for "mydomain.com" point to my anti-spam gateways. The anti-spam gateways then relay the email to my mail server. If someone sends an ...
1
vote
1answer
1k views

Exchange 2003 - Message delievery fails

I am having issues with sending mail to specifics domains. The bounce back message is: "Could not deliver the message in the time limit specified. Please retry or contact your administrator." ...
1
vote
2answers
409 views

User agent blacklist recommended

Perishable Press publishes a managed user agent blacklist frequently, which blocks bad bots which htaccess directives. Article to be found here: ...
1
vote
3answers
978 views

blacklisted exchange 2003

Our firewall failed about 3 weeks ago and while it was being replaced we were placed on the “cbl.abuseat.org” spam blacklist. Once we got the new firewall in and configured we were able to get ...
1
vote
1answer
168 views

How to re-establish the reputation of a compromised server?

Last week a server has been compromised. I have since fixed the problem, however the attackers managed to get my IP blacklisted. I have contacted all the blacklists I could find that listed the IP to ...
1
vote
1answer
215 views

My email server is blacklisted what can I do

I have discovered that my email server has been blacklisted by http://www.five-ten-sg.com What affect is that going to have on my sending and receiving emails and is there anything I can do about it ...
1
vote
2answers
2k views

Black Hole DNS on Windows DNS Server

I am looking at configuring our Windows DNS Servers for some type of DNS based blackhole operation. Ideally, we would be able to use feeds from MalwareDomains.com or the like. I was curious how one ...
1
vote
1answer
64 views

postfix disable blacklist checking for registered user

Many users has dynamic IP and sufficient number of these IP is blacklisted. How to disable check Postfix blacklist only for registered user? I want only block incoming mail from blacklisted IPS only. ...
1
vote
1answer
469 views

In postfix how can I conditionally enforce check_sender_access

I am servicing 2 virtual domains: domain1.org , domain2.org. I want to enforce the following policy: If a client connects from an IP address in $mynetworks then I want to allow only mails for which ...