I just figured this out myself in exim4 after a lot of reading about exim configuration. First, you want your app to add the following header: Return-Path: <bounced@yourdomain.com> Works with or without brackets. Exim will add brackets in the end either way. Second, this was the hard part. Exim always wanted to override my Return-Path: … Read more
I’m looking forward to seeing other answers to this question, but my feeling is that if you’re catching compromised mail accounts after only 40 spams have got through, you’re doing really well. I’m not sure I could detect similar abuse so quickly, and the prospect worries me. But I’m appalled that seven sets of credentials … Read more
formail, part of procmail (and probably already available on your system) can take a mailbox, split it up into messages, and then run a command on each one. From the man page: -s The input will be split up into separate mail messages, and piped into a program one by one (a new program is … Read more
Linux Malware Detect (http://www.rfxn.com/projects/linux-malware-detect/) installation is quite easy :). Go via this link, download http://www.rfxn.com/downloads/maldetect-current.tar.gz. The link to this file is located at the very top of the web-page. Then unzip this archive, go to newly created directory by running cd in your terminal. In the directory run sudo ./install.sh which will install the scanner … Read more
You will need to use a redirect router. Read the Exim Router specification, as it can do many things and thus can get quite complex. Basically, you will need to set something up like this (untested) sender_redirect: driver = redirect data = ${lookup{$sender_address}lsearch{/etc/exim4/sender_redirects}} Then create a file in /etc/exim4/sender_redirects that contains the redirects in a … Read more
On Debian-based systems exim logs data in /var/log/exim4/mainlog. You might find the eximstats tool useful for parsing and culling useful information out of that log file.
Assuming the error is complaining about the HELO/EHLO data, you want to use the helo_data option on the smtp transport. The default is $primary_hostname. remote_smtp: driver = smtp helo_data = host.example.com More information is available in the manual. If this isn’t the case, you probably want to include some example rejection messages. Just the three … Read more
Modern major mail services score spamminess based on multiple reputation factors, if available. If the only factor is your IP and you don’t mail often, this might be “the reputation of the /24 my IP is in”. If you mail a lot, you might get your own reputation. The easiest way to get reputation which … Read more
Your /etc/hosts file should have at least two records in it. The first record should be of the form: <IP_ADDRESS> <HOST_FQDN> <HOSTNAME> the second one should be of the form: 127.0.0.1 localhost You also need to make sure that your /etc/hostname file contains the server’s FQDN, and that running hostname -f returns your servers FQDN. … Read more
This is actually not explicitly defined anywhere, and whether or not the server should be “trusted” depends on the client (which could of course be another mail server) connecting to it; quoting from the relevant RFC (RFC 2487): If the SMTP client decides that the level of authentication or privacy is not high enough for … Read more