Support of IMAP ID command in mail proxy module?

[Michael Kliewe]

Hello,

I'm using the mail module of nginx to proxy and loadbalance IMAP+POP3 
connections to backend servers. I do authentication via http authentication.

Some Clients are sending IMAP ID commands to the server with information 
about their software and version. I would like to log that and maybe use 
that during authentication. It would be great if nginx would support 
that command, and if it has been sent before LOGIN, also provide the 
information to the http authentication script.
IMAP ID can be found in RFC 2971: http://www.faqs.org/rfcs/rfc2971.html

The information about the client could be used to route the user to a 
specific backend server that has some client-specific IMAP bug fixes in 
place, or could be used to restrict logins of a specific user to only 
one specific client if the user wants that for slightly higher security, 
or for a list of "last activity of the user" like GMail does, or just 
for client statistics.

I'm not a C programmer, so sadly I cannot write a patch myself for this, 
but maybe someone is able to add this small feature?

Thanks
Michael