Mastering Nginx

Using the Mail Module

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Combining with memcached

Depending on the frequency of clients accessing the mail services on your proxy

and how many resources are available to the authentication service, you may want

to introduce a caching layer into the setup. To this end, we will integrate memcached
as an in-memory store for authentication information.

NGINX can look up a key in memcached, but only in the context of a location in

the http module. Therefore, we will have to implement our own caching layer

outside of NGINX.

Authentication Request from NGINX

Is user/pass

in cache?

Retrieve value from cache

and return to NGINX

Store key/value

in memcached

No

Ye s

As the flowchart shows, we will first check whether or not this username/password

combination is already in the cache. If not, we will query our authentication store for
the information and place the key/value pair into the cache. If it is, we can retrieve

this information directly from the cache.

Zimbra has created a memcache module for NGINX that takes care of

this directly within the context of NGINX. To date, though, this code

has not been integrated into the official NGINX sources.