Linked Questions

1
vote
4answers
2k views

Prevent spamming [duplicate]

How to prevent spamming in Cpanel / Linux server ?
0
votes
1answer
82 views

Postfix forwards to Gmail being rate limited even with unmodified headers

I've installed Postfix on Ubuntu 14.04 with the defaults. I then configured some virtual aliases to forward email from a few addresses to various personal (mostly Gmail) accounts. This is just to make ...
2
votes
1answer
137 views

Does postfix reject spoofed senders?

Is there a reliable way to reject incoming mails with a spoofed e-mail address? What kind of checks does postfix run normally on incoming mails? does postfix check the reverse dns by default? does ...
0
votes
1answer
57 views

Prevent Email Going to Spam [duplicate]

I've set up my own server and I'm really struggling to stop any outgoing email go to spam. I've used allaboutspam and mail-tester.com to test it and they both come back with perfect results. No ...
13
votes
2answers
3k views

What are SPF records, and how do I configure them?

This is a canonical question about setting up SPF records. I have an office with many computers that share a single external ip (I'm unsure if the address is static or dynamic). Each computer ...
15
votes
2answers
980 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 ...
-4
votes
1answer
40 views

No way to create an effective spam filter [duplicate]

We are having a big spam problem and we don't know how to resolve it. We have one spammer that send us mail daily. All these emails are from different themes, using different email addresses that are ...
0
votes
1answer
81 views

Steps to make sure network is not blacklisted…Again

I have an interesting issue. I have a client that just got blacklisted due to spam being sent out over the last 2 days. I have my firewall configured to only allow mail to go outbound on port 25 ...
17
votes
5answers
444 views

Is it good practice or too draconian to reject mails from mailservers with no RDNS

I've recently dropped SpamAssassin and am now basing spam rejection on DNSRBL's, grey-listing and other basic tests and I'm wondering whether I should also block hosts that don't have a valid RDNS ...
0
votes
1answer
109 views

Project Honeypot says my mail server has become a spammer [duplicate]

I need help diagnosing this: http://www.projecthoneypot.org/ip_66.18.204.186 It says my server has been sending spam for 4 months! I try to be a responsible mail server admin, I hate spam, I do ...
0
votes
3answers
2k views

smtpd_helo_restrictions = …, reject_unknown_helo_hostname occasionally rejects mail I care about, how to handle?

I have configured my postfix as follows: smtpd_helo_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unknown_helo_hostname This is working well because most spambots don't seem ...
-1
votes
2answers
664 views

Postfix is Sending Spam [duplicate]

I have an Ubuntu 12.04 server, hosted on AWS, that powers a dozen WordPress installations using Nginx and php5-fpm. The problem just began one day. My server was down. Panic! Whenever I turned it on ...

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