isync is a commandline application which synchronizes a local maildir-style mailbox with a remote IMAP4 mailbox, suitable for use in IMAP-disconnected mode. Multiple copies of the remote IMAP4 mailbox can be maintained, and all flags are synchronized. TLS/SSL is supported via imaps: or STARTTLS.
> 403 means "access denied".
oh, really? *surprise surprise*
> Access modes don't change automatically or randomly.
explain this to the servers that have a different opinion.
> this looks like an ideal DoS tool.
there are more effective tools for such purposes ...
> It seems to keep retrying (at least a couple of times) after it has already been banned for flooding
> (does 403 reply really mean "try again until it works"?).
yes, 403 obviously sometimes is a transient error - otherwise i hadn't done it that way.
the retry logic should be a lot smarter and server-based, not url-based, as it is currently.
also, it should be possible to specify a per-server connection limit, not only a global one. i have already started working in this direction, but the usual permanent lack of time prevents me from finishing it any time soon.