add some resolver intro doc

diff --git a/doc/resolver-caching.rst b/doc/resolver-caching.rst
index 6bcc66df29a44ea6b8434654e2088ae82f139e05..f39b8ad911469d435e502cef7a4f81f796491e22 100644 (file)
--- a/doc/resolver-caching.rst
+++ b/doc/resolver-caching.rst
@@ -3,7 +3,15 @@
 Resolver Caching Classes
 ========================
 
-This is a placeholder.
+The dnspython resolver does not cache by default, but caching can be
+enabled by creating a cache and assigning it to the resolver's *cache*
+attribute.  If a cache has been configured, the resolver caches both
+positive and negative responses.  The cache respects the DNS TTL of
+the data, and will not return expired entries.
+
+Two thread-safe cache implementations are provided, a simple
+dictionary-based Cache, and an LRUCache which provides cache size
+control suitable for use in web crawlers.
 
 .. autoclass:: dns.resolver.Cache
    :members:

diff --git a/doc/resolver.rst b/doc/resolver.rst
index 7068bd30399a1834998122dc95359477e03c5f66..232ed66d2b2aa82142af51240cf07edc513a7aab 100644 (file)
--- a/doc/resolver.rst
+++ b/doc/resolver.rst
@@ -4,7 +4,11 @@
 Stub Resolver
 =============
 
-This is a placeholder.
+Dnspython's resolver module implements a "stub resolver", which does DNS
+recursion with the aid of a remote "full resolver" provided by an ISP
+or other service provider.  By default, dnspython will use the full
+resolver specifed by its host system, but another resolver can easily
+be used simply by setting the *nameservers* attribute.
 
 .. toctree::