How to capture the stderr of rsync and redirect it into a file?

[Hongyi Zhao]

Hi all,

See the following commands:

werner at debian:~$ rsync -c ftp.cn.debian.org::debian/ 2 >aaa
rsync: The server is configured to refuse --checksum (-c)
rsync error: requested action not supported (code 4) at clientserver.c
(849) [sender=3.0.9]
rsync: read error: Connection reset by peer (104)
rsync error: error in socket IO (code 10) at io.c(785) [Receiver=3.1.2dev]

Why rsync cann't let me redirect the stderr of it into a file, say, aaa, 
for this case?

Regards
-- 
.: Hongyi Zhao [ hongyi.zhao AT gmail.com ] Free as in Freedom :.