Unsolicited e-mail, comments or posts, often sent out in large volumes; possibly but not necessarily commercial in nature

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30
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6answers
45k 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 ...
45
votes
6answers
12k 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 ...
4
votes
1answer
1k views

Prevent mail being marked as spam

This is a canonical question about avoiding outgoing mail being classified as spam. I'm wondering how to prevent my emails from my site being marked as spam? I'm using sendmail. I'm trying to ...
67
votes
9answers
27k 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 ...
20
votes
4answers
4k 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 ...
8
votes
5answers
12k 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. ...
7
votes
4answers
4k 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 ...
0
votes
1answer
2k views

I can't send email from my server to gmail addresses

I'm using postfix, and have setup spf, dkim, and domainkeys. I can get my email to go to Yahoo, but not gmail. Here's the headers from an email send to Yahoo. Yahoo reports the email as domain key ...
5
votes
6answers
35k views

How do you detect a spambot on your network?

I help manage a small network of about 40 computers. We are running an Exchange 2003 mail server. What is the best way to find which machine is infected by a spambot? I've tried installing anti-virus ...
22
votes
7answers
13k 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 ...
4
votes
6answers
3k views

Send email on behalf of clients

We're a communications company primarily doing printing of statements / utility bills, then mailing them out in the post. A few clients have asked for e-Delivery. Pretty much take the print output as ...
7
votes
4answers
11k 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 ...
4
votes
2answers
1k views

Barracuda tagging email with 'date grossly in the future.'

I have a Barracuda 300. Granted it's running on some old firmware and the Energize updates are quite outdated. I'd like to update them, but, not my financial decision to do so. Starting around the ...
4
votes
1answer
632 views

How to stop backscatter email spam

I know I can't do anything about people spoofing my email address, but what can I do about all those annoying bounce-mails? I get 5-10 "Undeliverable mail" a day, but I don't know how I can filter ...
4
votes
2answers
9k views

Postfix check outgoing mail for spam

How can I force postfix to check (and log/flag/etc) all outgoing mail for spam? Just want to make sure I'm doing my part on my servers. EDIT: Postfix config, as requested. main.cf # See ...
3
votes
3answers
2k views

How do I spamtrap with Postfix?

How do I setup spamtraps with Postfix so clients that send to trapped addresses are prevented from sending me more spam?
2
votes
1answer
3k views

Is there any way to see why Outlook's client junk mail filter is marking a message as spam?

I have some users running Outlook 2007 connected to an Exchange server, and they're complaining about mail ending up in their junk box. There's no X-SCL tag in the mail headers so this filtering must ...
0
votes
5answers
2k views

Barracuda spam filter alternative - virtualization/appliance friendly?

I've sold and deployed Barracuda spam and web filters for years. I've always thought that the functionality was good (Barracuda Central, easy interface, effective filtering), but the hardware on the ...
3
votes
4answers
301 views

Minimize the chance my email is blocked/filtered as spam

I'm running a web-based store where order confirmations are sometimes blocked and don't reach the intended user. The structure of the business model is such that our product is marketed to the ...
0
votes
1answer
129 views

Spam coming from domain, but from a user that I don't have [duplicate]

Possible Duplicate: How to stop people from using my domain to send spam? I have google apps handling the email for my domain (musikpitch.com). Some Cialis spam got sent with the email ...
0
votes
2answers
422 views

Adding spam addresses to SpamHaus and SpamCop DNSRBL

I have a Postfix e-mail receiving server setup. I have applied the following setting in my Postfix main.cf file: smtpd_recipient_restrictions = reject_unauth_destination, reject_rbl_client ...
-1
votes
1answer
371 views

Hotmail blocks company emails, when hyperlink is inserted in the message body [closed]

I received the following results: ========================================================== Summary of Results ========================================================== SPF check: pass ...
6
votes
6answers
2k views

Spam prevention tips for Postfix

Without using SpamAssasin, or similar, what are your best tips for preventing spam. Please try and provide config examples :D
26
votes
7answers
3k 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 ...
35
votes
4answers
4k 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 ...
10
votes
5answers
7k 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 ...
6
votes
13answers
6k views

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

I know this sounds terrible, but I have a web app that has no users in the Philippines, but is constantly bombarded by spammers, carders testing cards, and other BS from there. I can see in the logs ...
10
votes
3answers
2k 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 ...
16
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 ...
7
votes
3answers
4k views

SMTP message rate control on Ubuntu 8.04, preferably with postfix

Maybe I am chasing a bug but I am trying to set up a smtp proxy of sorts. I have a postfix server which receives all the email for a collection of servers/clients. It them uses a smarthost ...
6
votes
7answers
6k views

Equivalent to denyhosts, but for HTTP requests?

My web server (apache2) is continually pounded by malicious bots, asking for URLs like these: ...
5
votes
5answers
5k views

Is there any alternative to SpamAssassin? [closed]

I'm looking for alternative to spamassassin. Anyone tried rspamd from Rambler.ru (https://bitbucket.org/vstakhov/rspamd/wiki/Home)?
5
votes
4answers
2k views

How do you test a new email filtering system?

What method do you use to test or evaluate potential new email filtering systems before you set it up on your production network? I am particularly interested in methods that are appropriate for ...
5
votes
2answers
884 views

Workaround SpamAssassin Y2K10 Bug (Mac OS X Server)

Bug Report: https://issues.apache.org/SpamAssassin/show_bug.cgi?id=6269 It turns out that SpamAssassin is adding a score of 3.2 (FH_DATE_PAST_20XX) to all email going through my mail server (Mac OS X ...
2
votes
2answers
185 views

Recommendations for an external email marketing service [closed]

First off, let me say that the small number of emails we send out are not spam. We include removal links and the emails are generally centered around free webinars that our marketing department hosts. ...
7
votes
2answers
13k 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 ...
6
votes
12answers
2k views

Recommendations for handling Directory Harvesting spam on Exchange 2003

Our Exchange server is getting slammed with anywhere between 450,000 and 700,000 spam messages per day. We receive about 1700 legitimate messages in the same time frame. Roughly 75% of the spam is ...
3
votes
2answers
851 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 ...
3
votes
5answers
223 views

What Security Suite to choose?

What security suite would you recommend in an environment consisting of roughly 120 PC's and some 30 servers? Environment is MS only, so Exchange and ISA must also be supported.
2
votes
2answers
1k views

How to limit the From header to match MAIL FROM in postfix?

SMTP clients are required to pass user authentication before sending emails to other domains (relay). And we can use smtpd_sender_restrictions to make sure the MAIL FROM address matches the ...
2
votes
5answers
5k views

Open Source or lower-cost alternatives to Barracuda Spam Filter

I'm aware of SpamAssassin-based solutions, but I'm looking for a free or low(er) cost spam filtering solution that's similar in functionality to the Barracuda Spam Filter. The Barracuda works well, ...
2
votes
4answers
220 views

Does sending e-mail in the name of customers increase the risk of being marked as spammer?

We are developing a SaaS website application that lets users send invoices to their clients. Ideally, these e-mails should appear to be originating from our customers, so the sender e-mail address ...
2
votes
5answers
1k views

Google marks seemingly perfect emails as spam

First post - was directed here from stackoverflow! The problem: Google marks seemingly correctly formatted emails from my apache/postfix server as spam. Sample email as follows; (I have replaced my ...
1
vote
2answers
2k views

Postfix - am I sending spam?

today I received like 30 messages within 5 minutes telling me that some mail I send could not be delivered, mostly to *.ru email addresses which I did not send any mail to. I have my own webserver ...
1
vote
2answers
4k views

Can I enforce mail rules server-side in Exchange 2007?

I have a client who gets a TON of spam to their public IP. I have put a Linux box running exim and spamassassin in front of it, and a bunch of Outlook rules to move mail into the Junk Email folder ...
0
votes
1answer
198 views

Do you need additional Security Products besides Forefront Security For Exchange Server

Does Forefront for Exchange Server 2010 cover the entire windows server or just the Exchange 2010 installation on a Windows 2008 R2 server? Do we need to run an additional Forefront product for full ...
0
votes
2answers
3k views

Yahoo flagging mail as spam when using relay server

I'm using Postfix to relay mail from my site to my mail server. Mail is received properly at my Gmail and Hotmail accounts - only Yahoo is the problem. The Yahoo mail headers state: Received-SPF: ...
0
votes
2answers
1k views

Block mails with local from-addresses from unauthenticated senders using courier-esmtpd

We run a small courier mail server (courier-esmtpd). It is configured to accept mail from authenticated clients without recipient restrictions and mail from everywhere to local addresses: ...
14
votes
2answers
914 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 ...
6
votes
2answers
210 views

DNSBLs for IPv6

Spamhaus and other well-known DNSBLs don't yet support IPv6, and I'm not sure they ever will. What alternatives are there for spam filtering on IPv6? One approach is to rely entirely on ...