Quarantine unsigned e-mails from own domain

[Joern Bredereck]

Hi,

we receive spoofed phishing emails that appear to be coming from our own domain. In order to filter or quarantine those spoofed emails I activated DKIM signatures for our own emails. Now that all "legitimate" e-mails from our domain are digitally signed via DKIM I was hoping I could filter or quarantine all e-mails from our domain that don't have a valid DKIM signature. But so far I haven't been able to create an appropriate filter in PMG.

Could someone help me, setting up a filter in PMG that would quarantine all e-mails from a certain domain, that don't have a (valid) DKIM signature?

Thanks in advance!

Jörn

 

[dcsapak]

you could increase the spamassassin score for that rule (something like DKIM_INVALID) but there is not really a filter for that
alternatively you could implement a dmarc policy on your domain too so failed dkim gets an even higher score out of the box