Hi,
now the problem is on nginx server(192.168.1.1) if i do
telnet localhost 143
. login user1 pass1
. OK [CAPABILITY IMAP4 User logged in
. select inbox
* FLAGS (\Answered \Flagged \Draft \Deleted \Seen)
* OK [PERMANENTFLAGS (\Answered \Flagged \Draft \Deleted \Seen \*)]
[b]* 0 EXISTS[/b]
...
if i do telnet to actual imap host(192.168.1.2)
telnet 192.168.1.2 143
. login user1 pass1
. OK [CAPABILITY IMAP4 User logged in
. select inbox
* FLAGS (\Answered \Flagged \Draft \Deleted \Seen)
* OK [PERMANENTFLAGS (\Answered \Flagged \Draft \Deleted \Seen \*)]
[b]* 1 EXISTS[/b]
...

and no error in nginx logs
nginx -V output is
nginx version: nginx/0.6.28
built by gcc 4.1.2 20071124 (Red Hat 4.1.2-42)
configure arguments: --user=nginx --group=nginx --prefix=/usr/share/nginx --sbin-path=/usr/sbin/nginx --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --http-client-body-temp-path=/var/lib/nginx/tmp/client_body --http-proxy-temp-path=/var/lib/nginx/tmp/proxy --http-fastcgi-temp-path=/var/lib/nginx/tmp/fastcgi --pid-path=/var/run/nginx.pid --lock-path=/var/lock/subsys/nginx --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_gzip_static_module --with-http_stub_status_module --with-http_perl_module --with-mail --with-mail_ssl_module --with-cc-opt=-O2 -g --add-module=/usr/src/redhat/BUILD/nginx-0.6.28/nginx-upstream-fair