So for those of you with capable mail clients (like OS X Mail.app), here’s proof that IMAP IDLE works for delivering push mail:
$ openssl s_client -connect imap.gmail.com:993 -crlf * OK Gimap ready for requests from 1.2.3.4 0123456789abcdef . capability * CAPABILITY IMAP4rev1 UNSELECT IDLE NAMESPACE QUOTA XLIST CHILDREN XYZZY . OK Thats all she wrote! 0123456789abcdef . login samj@samj.net letmein . OK samj@samj.net authenticated (Success) . examine inbox * FLAGS (\Answered \Flagged \Draft \Deleted \Seen) * OK [PERMANENTFLAGS ()] * OK [UIDVALIDITY 2] * 4498 EXISTS * 0 RECENT * OK [UNSEEN 1431] * OK [UIDNEXT 25141] . OK [READ-ONLY] inbox selected. (Success) . idle + idling ---mail sent and deleted here--- * 4499 EXISTS * 4499 EXPUNGE * 4498 EXISTS
This is invariably why some clients ‘feel’ more responsive than others, and why you should find an IMAP IDLE capable client.
