This is a simple Perl script for parsing DMARC aggregate reports from a set of email messages and summarizing them in a somewhat useful fashion.
Example output from dmarc-aggregate-parse -d umich.edu Maildir/.dmarc-reports/new/*:
-----------------------------------------------------------------------------
|*********************************umich.edu*********************************|
-----------------------------------------------------------------------------
Earliest timestamp: 2020-08-13 18:50:46
Latest timestamp: 2020-08-17 13:00:05
Total messages: 190287
DMARC disposition none: 190287
Aligned DKIM results:
fail: 66906
pass: 123381
Aligned DKIM successes:
umich.edu: 123354
Aligned SPF results:
fail: 22577
pass: 167710
Domain for aligned SPF successes:
bounce.c.alumni.umich.edu: 2697
icpsr.umich.edu: 21
slate-mx.umich.edu: 188
umich.edu: 164794
Recipient orgs:
google.com: 178753
Yahoo! Inc.: 9857
comcast.net: 1497
emailsrvr.com: 144
ZEROSPAM Security Inc.: 8
Mail sources (>2000 messages):
IP: 209.85.220.41
Hostname: mail-sor-f41.google.com.
Messages: 22175
DKIM fail: 1643
DKIM pass: 20532
SPF fail: 1793
SPF pass: 20382
IP: 35.162.59.88
Hostname: egress-host.a.mail.umich.edu.
Messages: 19408
DKIM fail: 7826
DKIM pass: 11582
SPF fail: 338
SPF pass: 19070
IP: 52.37.117.118
Hostname: egress-host.a.mail.umich.edu.
Messages: 19065
DKIM fail: 7711
DKIM pass: 11354
SPF fail: 305
SPF pass: 18760