What is the difference between SPF ~all and -all?

SPF is all about publishing a list of servers that are authorized to send on behalf of a domain. After writing out a list of servers in the form of an SPF record, the right thing to do is to end an SPF record with something that says "and everything else on the Internet is NOT authorized". The way the above is written is to use the "all" mechanism.  This mechanism matches everything.  By adding a prefix of "~" or…
3 October 2015