Sophos Email Gateway Allow CIDR
Email Gateway does not allow for CIDR allows, only blocks.
I have a customer using MailChimp, they do not advertise the URL of their sending servers - only their CIDR, as below:
As Sophos Email Gateway cannot add CIDR ranges, I would need to create a CSV with 86016 IP Addresses then import that into Sophos. This limitation is beyond unacceptable.
Support advise that you would need to grab the received address for each email that gets quarantined (header anomaly) and add that as an exception. Yes, you can add Wildcard exceptions *.mscv.net, however they use multiple email domains for sending and could make changes at any time and our customers would be impacted.
I think as a minimum please allow /24 subnets to /32 and at least you aren't giving your customers the ability to easily bypass the entire system.