2 ms·
If you set them at the top level, they should carry across the subdomains unless you configure them differently or override them with a subdomain specific recor
by brightball 5y ago
If you set them at the top level, they should carry across the subdomains unless you configure them differently or override them with a subdomain specific record.
You may want to verify that directly though. I haven't looked at the subdomain settings in a couple of years.
- dundarious 5y agoWhat if you do receive email for your domain but never for your subdomains, and therefore have necessary and non-"null" MX, etc., set up on the domain? Is there any point in having "null" records for the subdomains, and if so, is there any non-verbose way to do this? e.g., receiving emails at me@example.com, but never anything @sub1.example.com, @sub2.example.com, etc.
- zinekeller 5y agoUse wildcard reject SPF for nameserver entries, for example: example.net TXT "v=spf1 include:spf.yourmailprovider.example -all" *.example.net TXT "v=spf1 -all" and use strict DMARC policies. Unfortunately due to how DNS was defined, wildcard entries are not used whenever a subdomain is defined - even if its an A entry, so if you use an active subdomain (www is used most of the time) you unfortunately need to add them manually*. Also depending on your specific provider you may not be able to add them (unfortunately that's on them). * Except on, rather surprisingly, Microsoft's DNS servers (you can tick a box to force an wildcard entry to show up even if there are records already defined).
- dundarious 5y agoThanks, I do have several subdomain A records, but not a ton. I should get around to explicitly adding at least the SPF rejects for them.
- zinekeller 5y agoI do hope that an SPF2 will allow defining subdomains. Until then, this is the best defence.