I use Mailenable (Standard edition) to define mailboxes for domains hosted on my server and set all mailboxes so they redirect emails to the related users personal email address (ie tennis@echoridge.org forwards to something@gmail.com )
Recently spammers started sending spam emails pretending to be from tennis@echoridge.org but sent from their own servers. 2000+ failed spam emails came back to tennis@echoridge.org and were forwarded to the gmail.com address before I disabled tennis@echoridge.org
These spam emails caused our mail server IP address to appear on several blacklists and I believe caused gmail.com to lower the domain reputation of echoridge.org
I have tried blacklisting within Mailenable the spammers originating IP addresses but their IP addresses change too frequently AND this does not seem to help when failed emails come back from gmail.com or other ISPs.
What can I do within Mailenable (or otherwise) to stop failed spam spoofed emails that were not sent from my server from being redirected by Mailenable to other ISPs?
How prevent forwarding spam emails
Re: How prevent forwarding spam emails
First, are you sure the password isn't guessed and it's actually your server that sent the spam? In other words, check your SMTP logs for this user. If the e-mailadress is spoofed, your IP won't be blacklisted because it isn't originating from your server.
Second, is DKIM, DMARC and a good SPF record configured for this domain? If not, those would be the first steps for improving the security of your mail flow.
Second, is DKIM, DMARC and a good SPF record configured for this domain? If not, those would be the first steps for improving the security of your mail flow.
