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Questions tagged [spam]

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

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111 votes
9 answers
141k 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 ...
Billy Moon's user avatar
  • 1,437
111 votes
6 answers
67k 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 ...
Chris S's user avatar
  • 78.2k
99 votes
8 answers
198k 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 ...
kcode's user avatar
  • 1,845
82 votes
11 answers
91k 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 ...
Saif Bechan's user avatar
54 votes
5 answers
13k 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 ...
neu242's user avatar
  • 724
49 votes
5 answers
171k views

How do I check a PTR record?

I need to check a PTR record to make sure that a script I have is sending emails which will actually be received by my users and not be incorrectly marked as spam. I understand that the ISP which ...
Daisetsu's user avatar
  • 667
44 votes
7 answers
3k 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 ...
Stefan Seidel's user avatar
36 votes
7 answers
7k 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 ...
mailq's user avatar
  • 17.2k
31 votes
7 answers
6k 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 [email protected] as a from address. The customer wants it to use the email from the form as the from ...
Crab Bucket's user avatar
30 votes
6 answers
30k 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 ...
EJB's user avatar
  • 1,309
30 votes
4 answers
12k 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 ...
jonepatr's user avatar
  • 405
29 votes
2 answers
28k 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....
John Bachir's user avatar
  • 2,374
28 votes
4 answers
15k 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. ...
gravyface's user avatar
  • 14k
28 votes
4 answers
1k 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 ...
Ernie's user avatar
  • 5,352
26 votes
4 answers
138k 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 ...
Alex Reisner's user avatar
25 votes
7 answers
20k 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 ...
hsym's user avatar
  • 1,003
25 votes
5 answers
8k views

Does DKIM alone not solve the spam issue? Why do I need SPF?

FINAL EDIT : I was completely wrong about DKIM it seems, the signing domain does not have to be the same as the sender domain, thus the whole premise for my question is flawed. A lot of thanks to Paul ...
cornergraf's user avatar
23 votes
9 answers
44k 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 ...
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 ...
pooter03's user avatar
  • 436
20 votes
12 answers
46k 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....
coding Bott's user avatar
20 votes
1 answer
22k 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 ...
Uwe Keim's user avatar
  • 2,460
19 votes
9 answers
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 ...
Ryan Kearney's user avatar
17 votes
4 answers
4k 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' ...
Kevin Evans's user avatar
17 votes
2 answers
21k 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 ...
Tom Gullen's user avatar
16 votes
6 answers
4k views

Spam emails regarding Domain Abuse Notices

I have received domain abuse notice email from [email protected]. The mail asks to download a Word Document which I believe contains a virus. Dear Domain Owner, Our system has ...
AAgg's user avatar
  • 321
16 votes
3 answers
8k 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 ...
tlng05's user avatar
  • 255
15 votes
10 answers
7k 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 ...
Mikey1980's user avatar
  • 781
15 votes
5 answers
16k 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 (...
Tony Meyer's user avatar
14 votes
9 answers
25k 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 ...
chrism2671's user avatar
  • 2,649
14 votes
1 answer
43k 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 ...
Jim Miller's user avatar
14 votes
11 answers
21k views

Good & free Exchange spam filter [closed]

Do you know a good (and free, if possible) Microsoft Exchange 2003 spam filter?
Olivier Payen's user avatar
13 votes
7 answers
20k views

Are SPF needed for domains that do not send mails and do not have MX record?

I have some domains registered that do not send mails. I have totally removed MX record for these domains on my DNS. Is it still useful to set an SPF record in order to avoid spammer to send mails ...
Marco Demaio's user avatar
13 votes
2 answers
7k views

How can I reject base64 encoded spam email?

I just received couple of mails with similar content which were encoded with base64. Now I want to reject or discard these kind of emails using body check. Before I had in my body_checks something ...
user134969's user avatar
13 votes
2 answers
4k views

Detect spammers on my server

I recently got one Undelivered Mail Returned to Sender while sending my newsletter to one of my 1500 customers. My website uses a double-opt-in procedure to make sure, the user explicitly want to ...
koseduhemak's user avatar
13 votes
3 answers
61k views

Sendmail: Sender address rejected (Domain not found)

I'm running into problems with sending mail on our webserver. Some mails are sent and delivered without any problems (eg Gmail), while others are deferred with "Sender address rejected: Domain not ...
JonoCoetzee's user avatar
13 votes
2 answers
16k views

How does DKIM work when sending emails from multiple sources/servers?

So if I'm understanding DKIM correctly, it basically is a public/private key type of service. However, how does this work if you send emails from multiple servers/sources? For instance, I have a ...
Marc NJ's user avatar
  • 141
13 votes
5 answers
12k views

Is there any alternative to SpamAssassin? [closed]

I'm looking for an alternative to Spamassassin. Anyone tried rspamd ?
dynax60's user avatar
  • 139
13 votes
3 answers
50k views

All External Mail to Office 365 Fails SPF, Marked as Junk by EOP in a Hybrid Deployment

In short: legitimate emails are landing in Junk folders as EOP (Exchange Online Protection) stamps email messages as junk (SCL5) and SPF-failed. This happens with all external domains (e.g. gmail.com/...
wandersick's user avatar
12 votes
10 answers
6k 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 ...
Sheldon McGee's user avatar
12 votes
2 answers
18k views

Emails are constantly marked by Outlook.com as SPAM

One of our domains is constantly marked by Outlook as SPAM, despite the adequate setup that is reported as properly configured and validated by many on-line tools, among those, the mxtoolbox. Please ...
Zuul's user avatar
  • 273
12 votes
4 answers
1k 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: ...
Miguel Telleria de Esteban's user avatar
11 votes
5 answers
82k 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 ...
Brett Ryan's user avatar
11 votes
5 answers
14k views

Delete from mailq where subject matches

I have a mailq which is getting backed up with multiple emails with the same subject line. I would like to delete all emails in the mailq that match a particular subject line so they don't get sent. ...
David's user avatar
  • 851
11 votes
2 answers
794 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 ...
user39063's user avatar
  • 221
11 votes
4 answers
4k 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., [email protected]). All the out-of-office and spam rejection emails are coming back to me (...
Rob Cowell's user avatar
11 votes
1 answer
14k views

Postfix, how can I reject spam from unknown IP (no DNS)

Despite all efforts to filter spam, I'm still getting spam from unknown even after I've set main.cf to not allow it and to check the DNS etc. Even after adding a pcre: to REJECT /.unknown./ some of ...
Alienizer's user avatar
  • 111
11 votes
4 answers
28k 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 /usr/share/...
Glen Solsberry's user avatar
11 votes
3 answers
10k 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, ...
pablomedok's user avatar
11 votes
2 answers
15k views

How can I test if my apache server is an open proxy?

Is there a curl command that will validate if a server is acting as an open proxy? I've tried curl --proxy http://<my server>:80 http://yahoo.com But the response from apache is: ...
Will's user avatar
  • 362
10 votes
10 answers
6k 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 ...
Brent 's user avatar
  • 23.5k

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