$ fetchmail -p imap imap.comcast.net
Enter password for <email address hidden>:
fetchmail: couldn't find canonical DNS name of imap.comcast.net (imap.comcast.net): Temporary failure in name resolution
fetchmail: Query status=11 (DNS)
Even if you aren't using comcast for email this is a good way to test it, just use some made up password.
fetchmail is also affected e.g.
$ fetchmail -p imap imap.comcast.net
Enter password for <email address hidden>:
fetchmail: couldn't find canonical DNS name of imap.comcast.net (imap.comcast.net): Temporary failure in name resolution
fetchmail: Query status=11 (DNS)
Even if you aren't using comcast for email this is a good way to test it, just use some made up password.