In the past few days, I’ve noticed that some Sophos UTM firewalls I manage for clients haven’t been sending their daily reports (or other notification e-mails). When I first noticed this, checking my own SMTP proxy, I noticed that the e-mails were being sent from the firewalls, but were being dropped due to an SPF check failure.
Originally I thought this may have just been an overnight glitch with the DNS providers, however I later noticed that it’s stopped all e-mails coming from all the UTMs.
Further investigation, I realized that by default, the Sophos UTMs send their firewall notifications (and configuration backups) from the domain “fw-notify.net”, specifically, the e-mail address “[email protected]”. That’s when I had a brainfart and realized the e-mails weren’t being sent from my clients owned domains, but this fw-notify.net domain.
It appears that recently some SPF records have been created for the domain “fw-notify.net”, which is what is causing this issue. Also, I’m not quite sure if the domain underwent ownership change, or it his was overlooked by someone at Sophos.
I’m assuming numerous other longtime UTM users will be experiencing this as well.
To fix this, just log in to the problem UTMs, and change the notification Sender address as shown below to a domain you own. I changed mine to [email protected] (which has valid SPF since it’s my domains relay).