SPF checker
Shows your SPF record, follows every include, and counts the DNS lookups a receiving server actually makes. Over 10 and the record stops working.
The rest of the domain
Watch this domain for changes with Sender Guard. Free for 3 domains.
What it checks
The 10-lookup limit. Each include, a, mx, exists and redirect costs one DNS lookup, and so does every one nested inside an include. Past 10, receivers return a permanent error and treat SPF as failed.
Void lookups. More than two mechanisms pointing at names with no records is also a permanent error.
The ending. -all or ~all tells receivers to distrust everyone not listed. +all authorizes the whole internet.
One record only. Two SPF records on the same name invalidate both.
Other checks
SPF checker DMARC checker DKIM checker MX lookup Full domain report