I’ve recently signed up for an email forwarding service w/ aliases so that I can keep my true email address private when I sign up for new websites and services. I should clarify that I’m less concerned about concealing my identity as I am about protecting my real email address, identifying who leaked my info when my email address is compromised, and being able to stop the spam by turning off that alias.

While updating my existing profiles to point to aliases instead of my real address, I’ve hit a snag - some sites (Steam, Slack, etc) won’t allow me to update my email address to any known domains from my email forwarding service.

On these sites that block email forwarding addresses, for now I’m either updating my existing email address w/ a plus sign if the website allows it, otherwise I’m just leaving my existing email address unchanged. It’s not the end of the world, they already have my real email address, and I can probably go a Very Long Time without needing to check those inboxes anyway, but I’m still miffed that I can’t completely migrate my existing accounts to my new scheme.

I’ve read numerous posts about the benefits of custom domains to enable portability of email service providers, and I’m wondering if custom domains are the answer to these sites that disallow forwarding addresses, but I have questions:

• How do other people deal with this situation?
• Do these websites that block known email forwarding domains typically work on a whitelist or blacklist model? If the former (whitelist), then I’m thinking a custom domain will have the same problem, but if the latter (blacklist), then I reckon a custom domain with catchall might work.
• Particularly owners of custom domains, do you find your custom domain is allowed more often than not or do you run into the same problem?

EDIT: Clarified my objectives.