If one enabled DKIM, then using qpsmtpd-print-dns will provide a long string of the form:
default._domainkey IN TXT "v=DKIMA;p=<longkey>;[b]t=y[/b]"
...
Notice the t=y option in the end. When I first encountered it, I took the quick and dirty road to figure out what that does, by feeding the entire DKIM record in
http://dkimcore.org/c/keycheckOn that site, I was informed that "The 'y' flag tells recipients to ignore your DKIM signature". Which for me meant that I should omit the ";t=y" from the DNS TXT entry.
Checking things out today, I noticed that a DKIM signed message also includes a t= field, which is a timestamp though. All in all:
1) is this a case of a field used differently on the DKIM DNS TXT entry, compared to how it is used on DKIM-signed messages?
2) Did I do right to remove t=y from the DKIM DNS record?