nginx does not close the connection to backend pop3 server

[Igor Sysoev]

On Tue, Jul 24, 2007 at 10:16:03AM +0800, Joe Wong wrote:

> I am evaluating nginx pop3 proxy function and encounter 1 problem. Here 
> is my setup:
> 
> OS: RedHat FC7 2.6.21-1.3194.fc7 #1 SMP Wed May 23 22:35:01 EDT 2007 
> i686 i686 i386 GNU/Linux
> GCC: gcc version 4.1.2 20070502 (Red Hat 4.1.2-12)
> Nginx version: 0.5.26
> Config option: --with-debug --with-mail --with-select_module
> 
> Nginx config:
> daemon on;
> user root;
> worker_processes 10;
> 
> error_log logs/error.log debug;
> pid       logs/nginx.pid;
> 
> #maximum total connections of each worker
> events {
>    worker_connections 100;
> #    use select;
>    debug_connection 127.0.0.1;
> }
> 
> mail {
>    auth_http   localhost:8088/auth.php;
> 
>    pop3_capabilities  "TOP"  "USER";
>    pop3_auth          plain;
>    imap_capabilities  "IMAP4rev1"  "UIDPLUS";
> 
>    #pop3 configuration
>    server {
>        listen     110;
>        protocol   pop3;
>        proxy      on;
>    }
> }
> 
> 
> Test case:
> - A mailbox with message around 10M large
> - Use telnet to port 110, issue the USER/PASS command to login
> - Issue RETR 1 to download the 10M message
> - Close the connection by pressing Ctrl-] then 'q' right after RETR 
> command is issued
> 
> At this time,  Netstat shows that the connection from nginx to the 
> backend POP3 server remains connected.
> 
> Now, I repeat the above test case with "use select" turns on in 
> nginx.conf.  This time, I don't see the connection to backend pop3 
> remains after my client connection to nginx is terminated in the middle. 
> I suspect this is something to do with epoll call?
> 
> I only did the test on POP3 proxy, not sure if it has the same behaviour 
> on HTTP.
> 
> Please let me know if you need more information.

Could you create debug logs for epoll and select cases, and send them to me ?


-- 
Igor Sysoev
http://sysoev.ru/en/