[tayiorrobinson]

I did training provided by a large email security firm, and one thing the presenter said was along the lines of "this spam filter defaults to block the senders domain & IP, you can set an expiration on that block butI don't see a reason why you would". One misconfigured server sending out a single email and I assume by extension someone impersonating your domain could get you perma-blocked from sending emails to that company, and I assume it'd reduce your trust rating for other orgs using that provider.