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86
votes
9answers
71k views

How to stop people from using my domain to send spam? [duplicate]

I receive Mailer Daemon messages saying certain emails fail. My domain is itaccess.org which is administered by Google apps. Is there any way I can identify who is sending emails from my domain, and ...
79
votes
6answers
40k views

Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User?

This is a Canonical Question about Fighting Spam. Also related: How to stop people from using my domain to send spam? What are SPF records, and how do I configure them? There are so ...
69
votes
10answers
80k views

Dealing with HTTP w00tw00t attacks

I have a server with apache and I recently installed mod_security2 because I get attacked a lot by this: My apache version is apache v2.2.3 and I use mod_security2.c This were the entries from the ...
53
votes
6answers
88k views

How to send emails and avoid them being classified as spam?

This is a canonical question about how to handle email sent from your server being misclassified as spam. For additional information you may find these similar questions helpful: Best ...
42
votes
4answers
7k views

Is greylisting still an efficient method for preventing spam?

I've used greylisting on my servers for many years, but I don't know how effective it is nowadays. Is it still good for fighting spam in 2012? Or is the typical spammer MTA capable of resending ...
33
votes
5answers
585 views

Is it becoming impossible to be a small mail provider?

I operate a small mail server for my private emails, some friends who have websites and two NGOs. In total my server sends between 60 and 400 messages a day. Now a lot of these emails are personal ...
30
votes
7answers
3k views

How can I attract more Spammers hitting my Spam traps?

Currently I have a number or domains that are set up as Email Spam traps. So if I get mails on that domains I can be certain that it is ~100% Spam. I'm using this information to temporarily defer ...
28
votes
7answers
4k views

Why is it a bad idea to use a customer email as the from address

I've got an application that emails users once they have filled in a form. It uses a no-reply@customerdomain.com as a from address. The customer wants it to use the email from the form as the from ...
27
votes
4answers
722 views

What happened to all the spam?

Don't get me wrong, I'm mostly glad that this happened. However, I want to make sure that the reasons for it happening are sound - rather than there being a problem with our methods. I'd like to ...
25
votes
7answers
16k views

How to stop spammers from sending spam as me

We've starting to receive bounced spam messages and the sender is one of our email address. We know that we don't send spam from that address. We've tried changing the password but we're still ...
23
votes
4answers
9k views

Best Practices for preventing you from looking like a spammer [duplicate]

I'd like to feel more confident setting up mail for my clients with regards to false positives. Here's what I know: SPF records are good, but not every spam filter service/software (SFSS) uses them....
21
votes
12answers
29k views

Which anti spam DNS blacklists should used?

i want to protect my mailserver with dns blacklists for fighting the spam. there a so many blacklists out there. currently i use: ix.dnsbl.manitu.net cbl.abuseat.org bl.spamcop.net safe.dnsbl.sorbs....
20
votes
7answers
11k views

Why do 'hackers' setup bots repeatedly fill out web forms?

There is something I don't get, one of my web apps has a small form that allows you to enter you name and email address to "subscribe" to a user list for a site I maintain. The site is very low ...
20
votes
4answers
2k 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 ...
18
votes
4answers
72k views

Fixing My MTA's Poor Reputation

I have a web site that needs to send email to customers to deliver files that they have purchased. Reliable email delivery is vital to this business. Unfortunately, most of the emails sent by my ...
17
votes
9answers
2k views

Gmail and Live are making all messages from my server as spam

I'm getting very weird results here. When my server sends an email to my @hotmail or @gmail account, it's marked as spam. When I send email through my server from Outlook to @hotmail, it doesn't get ...
16
votes
3answers
2k views

Is my new gTLD causing it to get filtered as spam?

I have a domain called "*******.international". I decided to go with the new gTLD because it fits the name of the company pretty well. I have an automated emailer setup to send emails to our clients' ...
16
votes
2answers
35k views

How do I check a reverse PTR record?

I need to check a reverse PTR record to make sure that a script I have is sending emails which will actually received by my users and not incorrectly marked as spam. I understand that the ISP which ...
14
votes
11answers
17k views

Good & free Exchange spam filter [closed]

Do you know a good (and free, if possible) Microsoft Exchange 2003 spam filter?
14
votes
3answers
3k views

Prevent mail being marked as spam

This is a canonical question about avoiding outgoing mail being classified as spam. Also related: Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User? What ...
13
votes
10answers
4k views

Using fake MX records to combat spam

I have a client that is getting heavily spammed.. It's the 15th of the month and POP3 bandwidth is almost 100 GB. There are only 7 e-mail accounts on this domain. I installed SpamAssassin set it to 5 ...
13
votes
2answers
5k views

Is the 10-DNS-lookup limit in the SPF spec typically enforced?

My understanding is that the SPF spec specifies an email receiver shouldn't have to do more than 10 DNS lookups in order to gather all the allowed IPs for a sender. So if an SPF record has include:foo....
12
votes
10answers
5k views

Where to go to see if my IP is blacklisted as a SPAM

This has happened before and some mail servers will tell you that your IP has been blacklisted (RBL, CBL, etc) but I can't find that site to check anymore and searches result in a site that may or may ...
11
votes
2answers
731 views

How can I reduce the damage of stolen mail accounts?

Currently I’m offering some webhosting to a few advertising agencies for their premium customers. But currently I have a great problem with the E-Mail Service. In the last week, the E-Mail Accounts of ...
11
votes
3answers
5k views

Gmail rejects emails. Openspf.net fails the tests

I've got a problem with Gmail. It started after one of our trojan infected PCs sent spam for one day from our IP address. We've fixed the problem, but we got into 3 black lists. We've fixed that, ...
11
votes
3answers
612 views

Email from our server tagged as junk by Hotmail Smartscreen unable to inform Hotmail that it is legitimate

Since more than 1 month ago we are having our email from one of our servers systematically tagged as junk by Hotmail Smartscreen filter. We have taken the following actions/measures without success: ...
10
votes
10answers
3k views

Setting up a fake email address to trap spammers

I have heard it suggested that we set up a special email address, with it's only purpose being to be harvested. Then blacklisting every sender that targets this address. I'm wondering: if anyone ...
10
votes
7answers
2k views

Does SMTP greylisting a) stop much spam and b) stop much legitimate mail?

I've just set up an SMTP server on a relatively little used domain using Postfix and enabled greylisting with SQLGrey. So far it seems to be working OK, and while there's the slight irritation of ...
10
votes
4answers
3k views

How I stop spam backscatter rendering email on my domain unusable?

Some miscreant is using non-existent accounts on my domain as a forged sender for spam emails (i.e., sdfhdfsg@mydomain.com). All the out-of-office and spam rejection emails are coming back to me (...
10
votes
5answers
2k views

Recommendations for SMTP services for massive mailing [closed]

What is the recommendations for SMTP services for massive mailing? Let me clarify, most of the free SMTP services (Gmail, Yahoo, Hotmail, etc...) has limits about the amount of messages you can send ...
10
votes
5answers
7k views

Is there any alternative to SpamAssassin? [closed]

I'm looking for an alternative to Spamassassin. Anyone tried rspamd ?
10
votes
1answer
10k views

What is preferable, “no-reply@” or “noreply@”? [closed]

Having a service that sends out notifications to users, I'm currently thinking about changing the sender email address from "info@" to something more meaningful. Since a reply never makes sense, I'm ...
10
votes
1answer
400 views

Microsoft is blocking mail from entire netblock. ISP doesn't know what to do?

I recently moved a client from basic T1 service to a multi-site MPLS solution with same vendor. The ISP, XO Communications, provided a decade of stable service as a T1 provider. The process of moving ...
10
votes
5answers
9k views

How to minimise SpamAssassin (spamd) memory use

I'm using SpamAssassin on Debian (the default configuration with Pyzor, AWL and Bayes disabled, and sa-compile enabled), and each of the spamd child processes consume around 100 to 150MB of memory (...
9
votes
10answers
13k views

Relatively easy way to block all traffic from a specific country?

I have a web app that has no users in the Philippines, but is constantly bombarded by spammers, carders testing cards, and other undesirable activity from there. I can see in the logs that they have ...
9
votes
5answers
14k views

How do I configure SPF for multiple domains on a server? (also allowing gmail as a sender)

SPF (Sender Policy Framework) seems like a good way to combat spammers/spoofing. However, despite reading the explanations several times, I'm not quite understanding how to configure it correctly. ...
9
votes
2answers
5k views

IIS7 ban IP range [duplicate]

Possible Duplicate: How does IPv4 Subnetting Work? I have a list of IP ranges I would like to ban, an example being: 119.30.47.xx Where xx is anything. I've added the domain and IP ...
9
votes
1answer
210 views

Postfix emails detected as spam with gmail [duplicate]

I know that there are a few posts about this and I have been reading them for a while now but still, I can't resolve my issue. I’m running ISPconfig with postfix and I can’t figure out why my ...
9
votes
1answer
365 views

Is there a way to get spamassassin to score the top lines of a message body more heavily?

A lot of spam is getting through the filter on the mail server I run with the relatively simple trick of starting with few lines of (incredibly obvious) weight loss or other scam text at the top, ...
8
votes
9answers
11k views

My EC2 instance's email is being spam blocked by gmail

I'm not sure what to do about this. When on a different IP (the same server set up, domain etc), we had no problems with email deliverability. Since transferring to EC2, despite having the AWS imposed ...
8
votes
4answers
14k views

How does a Reverse DNS lookup work with regards to spam filters?

I have heard that most spam filters use a reverse DNS lookup on the originating IP address of the sending SMTP server (or something like that) as part of the verification process. I want to make sure ...
8
votes
6answers
13k views

All my emails to Yahoo!, Hotmail and AOL are going to Spam, though I've implemented every validation method (works for Gmail though)

I've implemented everything and checked everything (SPF, DomainKey, DKIM, reverse lookup), and only Gmail is allowing my emails to go to Inbox. Yahoo, Hotmail and AOL are all sending my messages to ...
7
votes
3answers
2k views

Should I let email bounce or send it to a blackhole?

I have a lot of unused (old, dead) accounts on my machine. Many of them receive literally thousands of emails a day, all spam. If the account was used by a person, I let the email bounce so that ...
7
votes
4answers
2k views

Why does my mail get marked as spam?

I Have the server "afspraakmanager.be". It matches everything not to be a spam server.(it isn't by the way): it has reverse dns, spf,dkim,... . But hotmail marks it as spam. I think the problem is ...
7
votes
3answers
197 views

Is SRS rewriting absolutely necessary for a forwarding mailserver?

I am operating a Postfix email server for my domain, say mydomain.com. It mostly acts as a forwarding email server: users receive an email address @mydomain.com, but usually elect to have their ...
7
votes
1answer
22k views

How to resolve problems with spf / softfail?

I'm having problems with Google rejecting mail because of SPF problems. I thought I had this fixed, but evidently not... The mail is being sent from a Drupal site running mimemail. A message that ...
7
votes
2answers
3k views

GMail suspects confirmation email in stealing personal information

When user registers on my web site, web site sends user email confirmation link. Subject: Please confirm your email address Body:Please open this link in your browser to confirm your email address: ...
7
votes
4answers
7k views

What to do with an out-of-warranty Barracuda Spam/Web filter?

I'm working with an organization that would like to start using a old Barracuda Spam Filter 300 unit. I've sold and configured plenty of these, but was surprised to see that this unit's warranty ...
7
votes
3answers
224 views

Does “~all” in the middle of an SPF record signal the end of the record when it is parsed?

Our company's SPF record format is as follows: "v=spf1 include:_spf.google.com ~all a mx ip4:X.X.0.0/23 include:spf.example.com ?all" So we have an "~all" in the middle of our SPF record. On the ...
7
votes
4answers
12k 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 ...