Linked Questions

0
votes
1answer
52 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 ...
14
votes
2answers
910 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 ...
2
votes
1answer
118 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 ...
-4
votes
1answer
39 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
99 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 ...
-1
votes
2answers
517 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 ...
0
votes
2answers
154 views

Many invalid HELO from

I've been recieving many invalid helo requests from a Microsoft domain. I already did send a question about this but they still do not respond. maillog: Jan 14 19:27:14 relay postfix/smtpd[57104]: ...
0
votes
1answer
80 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
429 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 ...
6
votes
4answers
884 views

How can I block outside mail FROM postmaster@mydomain.com?

A security firm has been testing my mail server and claims my Postfix daemon is an open relay. The evidence is as follows (valid public IP for mail.mydomain.com has been changed to 10.1.1.1 for ...
-1
votes
1answer
505 views

sendmail - Server Sending Spam? [duplicate]

for the past day my server is being used to send a spam. I'm using the Amazon Linux Distro (RedHat based). It has sendmail 8.14.4. It is setup to require authentication, SSL etc. Below are some ...
-1
votes
1answer
932 views

Suddenly Gmail and Hotmail block our emails [duplicate]

Starting from yesterday, all emails sent from our server are being rejected by Gmail and Hotmail. Everything was working properly until now. Here are the error messages received: Gmail Failed ...

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